diff --git a/libs/core/Makefile b/libs/core/Makefile
index bf74eadd9e0..9841b83beee 100644
--- a/libs/core/Makefile
+++ b/libs/core/Makefile
@@ -15,7 +15,7 @@ test tests:
 	-u LANGCHAIN_API_KEY \
 	-u LANGSMITH_TRACING \
 	-u LANGCHAIN_PROJECT \
-	uv run --group test pytest -n auto --disable-socket --allow-unix-socket $(TEST_FILE)
+	uv run --group test pytest -vv -s -n auto --disable-socket --allow-unix-socket $(TEST_FILE)
 
 test_watch:
 	env \
diff --git a/libs/core/langchain_core/_api/deprecation.py b/libs/core/langchain_core/_api/deprecation.py
index fcbfc58b38f..4b3a848c550 100644
--- a/libs/core/langchain_core/_api/deprecation.py
+++ b/libs/core/langchain_core/_api/deprecation.py
@@ -23,6 +23,7 @@ from typing import (
     cast,
 )
 
+from pydantic.fields import FieldInfo
 from typing_extensions import ParamSpec
 
 from langchain_core._api.internal import is_caller_internal
@@ -39,8 +40,7 @@ class LangChainPendingDeprecationWarning(PendingDeprecationWarning):
 # PUBLIC API
 
 
-# Last Any should be FieldInfoV1 but this leads to circular imports
-T = TypeVar("T", bound=Union[type, Callable[..., Any], Any])
+T = TypeVar("T", bound=Union[type, Callable[..., Any], FieldInfo])
 
 
 def _validate_deprecation_params(
@@ -152,10 +152,6 @@ def deprecated(
         _package: str = package,
     ) -> T:
         """Implementation of the decorator returned by `deprecated`."""
-        from langchain_core.utils.pydantic import (  # type: ignore[attr-defined]
-            FieldInfoV1,
-            FieldInfoV2,
-        )
 
         def emit_warning() -> None:
             """Emit the warning."""
@@ -228,7 +224,7 @@ def deprecated(
                 )
                 return cast("T", obj)
 
-        elif isinstance(obj, FieldInfoV1):
+        elif isinstance(obj, FieldInfo):
             wrapped = None
             if not _obj_type:
                 _obj_type = "attribute"
@@ -240,28 +236,7 @@ def deprecated(
             def finalize(wrapper: Callable[..., Any], new_doc: str) -> T:  # noqa: ARG001
                 return cast(
                     "T",
-                    FieldInfoV1(
-                        default=obj.default,
-                        default_factory=obj.default_factory,
-                        description=new_doc,
-                        alias=obj.alias,
-                        exclude=obj.exclude,
-                    ),
-                )
-
-        elif isinstance(obj, FieldInfoV2):
-            wrapped = None
-            if not _obj_type:
-                _obj_type = "attribute"
-            if not _name:
-                msg = f"Field {obj} must have a name to be deprecated."
-                raise ValueError(msg)
-            old_doc = obj.description
-
-            def finalize(wrapper: Callable[..., Any], new_doc: str) -> T:  # noqa: ARG001
-                return cast(
-                    "T",
-                    FieldInfoV2(
+                    FieldInfo(
                         default=obj.default,
                         default_factory=obj.default_factory,
                         description=new_doc,
diff --git a/libs/core/langchain_core/language_models/chat_models.py b/libs/core/langchain_core/language_models/chat_models.py
index 712271778ae..4df6a04e7b4 100644
--- a/libs/core/langchain_core/language_models/chat_models.py
+++ b/libs/core/langchain_core/language_models/chat_models.py
@@ -75,7 +75,6 @@ from langchain_core.utils.function_calling import (
     convert_to_json_schema,
     convert_to_openai_tool,
 )
-from langchain_core.utils.pydantic import TypeBaseModel, is_basemodel_subclass
 
 if TYPE_CHECKING:
     import uuid
@@ -625,7 +624,7 @@ class BaseChatModel(BaseLanguageModel[BaseMessage], ABC):
         stop: Optional[list[str]] = None,
         **kwargs: Any,
     ) -> dict:
-        params = self.dict()
+        params = self.model_dump()
         params["stop"] = stop
         return {**params, **kwargs}
 
@@ -1298,7 +1297,7 @@ class BaseChatModel(BaseLanguageModel[BaseMessage], ABC):
         """Return type of chat model."""
 
     @override
-    def dict(self, **kwargs: Any) -> dict:
+    def model_dump(self, **kwargs: Any) -> dict:
         """Return a dictionary of the LLM."""
         starter_dict = dict(self._identifying_params)
         starter_dict["_type"] = self._llm_type
@@ -1456,9 +1455,9 @@ class BaseChatModel(BaseLanguageModel[BaseMessage], ABC):
                 "schema": schema,
             },
         )
-        if isinstance(schema, type) and is_basemodel_subclass(schema):
+        if isinstance(schema, type) and issubclass(schema, BaseModel):
             output_parser: OutputParserLike = PydanticToolsParser(
-                tools=[cast("TypeBaseModel", schema)], first_tool_only=True
+                tools=[schema], first_tool_only=True
             )
         else:
             key_name = convert_to_openai_tool(schema)["function"]["name"]
diff --git a/libs/core/langchain_core/language_models/llms.py b/libs/core/langchain_core/language_models/llms.py
index 87f3974ae1c..8782268cb74 100644
--- a/libs/core/langchain_core/language_models/llms.py
+++ b/libs/core/langchain_core/language_models/llms.py
@@ -528,7 +528,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         else:
             prompt = self._convert_input(input).to_string()
             config = ensure_config(config)
-            params = self.dict()
+            params = self.model_dump()
             params["stop"] = stop
             params = {**params, **kwargs}
             options = {"stop": stop}
@@ -598,7 +598,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
 
         prompt = self._convert_input(input).to_string()
         config = ensure_config(config)
-        params = self.dict()
+        params = self.model_dump()
         params["stop"] = stop
         params = {**params, **kwargs}
         options = {"stop": stop}
@@ -941,7 +941,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
             ] * len(prompts)
             run_name_list = [cast("Optional[str]", run_name)] * len(prompts)
         run_ids_list = self._get_run_ids_list(run_id, prompts)
-        params = self.dict()
+        params = self.model_dump()
         params["stop"] = stop
         options = {"stop": stop}
         (
@@ -1193,7 +1193,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
             ] * len(prompts)
             run_name_list = [cast("Optional[str]", run_name)] * len(prompts)
         run_ids_list = self._get_run_ids_list(run_id, prompts)
-        params = self.dict()
+        params = self.model_dump()
         params["stop"] = stop
         options = {"stop": stop}
         (
@@ -1400,7 +1400,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         """Return type of llm."""
 
     @override
-    def dict(self, **kwargs: Any) -> dict:
+    def model_dump(self, **kwargs: Any) -> dict:
         """Return a dictionary of the LLM."""
         starter_dict = dict(self._identifying_params)
         starter_dict["_type"] = self._llm_type
@@ -1427,7 +1427,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         directory_path.mkdir(parents=True, exist_ok=True)
 
         # Fetch dictionary to save
-        prompt_dict = self.dict()
+        prompt_dict = self.model_dump()
 
         if save_path.suffix == ".json":
             with save_path.open("w") as f:
diff --git a/libs/core/langchain_core/output_parsers/base.py b/libs/core/langchain_core/output_parsers/base.py
index a14a10829f9..038b43d6267 100644
--- a/libs/core/langchain_core/output_parsers/base.py
+++ b/libs/core/langchain_core/output_parsers/base.py
@@ -324,9 +324,9 @@ class BaseOutputParser(
         )
         raise NotImplementedError(msg)
 
-    def dict(self, **kwargs: Any) -> dict:
+    def model_dump(self, **kwargs: Any) -> dict:
         """Return dictionary representation of output parser."""
-        output_parser_dict = super().dict(**kwargs)
+        output_parser_dict = super().model_dump(**kwargs)
         with contextlib.suppress(NotImplementedError):
             output_parser_dict["_type"] = self._type
         return output_parser_dict
diff --git a/libs/core/langchain_core/output_parsers/json.py b/libs/core/langchain_core/output_parsers/json.py
index 84f510f331d..38ae28d00f6 100644
--- a/libs/core/langchain_core/output_parsers/json.py
+++ b/libs/core/langchain_core/output_parsers/json.py
@@ -4,11 +4,10 @@ from __future__ import annotations
 
 import json
 from json import JSONDecodeError
-from typing import Annotated, Any, Optional, TypeVar, Union
+from typing import Any, Optional
 
 import jsonpatch  # type: ignore[import-untyped]
-import pydantic
-from pydantic import SkipValidation
+from pydantic import BaseModel, SkipValidation
 
 from langchain_core.exceptions import OutputParserException
 from langchain_core.output_parsers.format_instructions import JSON_FORMAT_INSTRUCTIONS
@@ -19,18 +18,6 @@ from langchain_core.utils.json import (
     parse_json_markdown,
     parse_partial_json,
 )
-from langchain_core.utils.pydantic import IS_PYDANTIC_V1
-
-if IS_PYDANTIC_V1:
-    PydanticBaseModel = pydantic.BaseModel
-
-else:
-    from pydantic.v1 import BaseModel
-
-    # Union type needs to be last assignment to PydanticBaseModel to make mypy happy.
-    PydanticBaseModel = Union[BaseModel, pydantic.BaseModel]  # type: ignore[assignment,misc]
-
-TBaseModel = TypeVar("TBaseModel", bound=PydanticBaseModel)
 
 
 class JsonOutputParser(BaseCumulativeTransformOutputParser[Any]):
@@ -43,18 +30,16 @@ class JsonOutputParser(BaseCumulativeTransformOutputParser[Any]):
     describing the difference between the previous and the current object.
     """
 
-    pydantic_object: Annotated[Optional[type[TBaseModel]], SkipValidation()] = None  # type: ignore[valid-type]
+    pydantic_object: SkipValidation[Optional[type[BaseModel]]] = None
     """The Pydantic object to use for validation.
     If None, no validation is performed."""
 
     def _diff(self, prev: Optional[Any], next: Any) -> Any:
         return jsonpatch.make_patch(prev, next).patch
 
-    def _get_schema(self, pydantic_object: type[TBaseModel]) -> dict[str, Any]:
-        if issubclass(pydantic_object, pydantic.BaseModel):
+    def _get_schema(self, pydantic_object: type[BaseModel]) -> dict[str, Any]:
+        if issubclass(pydantic_object, BaseModel):
             return pydantic_object.model_json_schema()
-        if issubclass(pydantic_object, pydantic.v1.BaseModel):
-            return pydantic_object.schema()
         return None
 
     def parse_result(self, result: list[Generation], *, partial: bool = False) -> Any:
diff --git a/libs/core/langchain_core/output_parsers/openai_functions.py b/libs/core/langchain_core/output_parsers/openai_functions.py
index f71b2c8044b..8bca4ff0492 100644
--- a/libs/core/langchain_core/output_parsers/openai_functions.py
+++ b/libs/core/langchain_core/output_parsers/openai_functions.py
@@ -274,10 +274,7 @@ class PydanticOutputFunctionsParser(OutputFunctionsParser):
                 pydantic_schema = self.pydantic_schema[fn_name]
             else:
                 pydantic_schema = self.pydantic_schema
-            if hasattr(pydantic_schema, "model_validate_json"):
-                pydantic_args = pydantic_schema.model_validate_json(_args)
-            else:
-                pydantic_args = pydantic_schema.parse_raw(_args)
+            pydantic_args = pydantic_schema.model_validate_json(_args)
         return pydantic_args
 
 
diff --git a/libs/core/langchain_core/output_parsers/openai_tools.py b/libs/core/langchain_core/output_parsers/openai_tools.py
index b4f845bdcad..0cfbe7d8149 100644
--- a/libs/core/langchain_core/output_parsers/openai_tools.py
+++ b/libs/core/langchain_core/output_parsers/openai_tools.py
@@ -4,9 +4,9 @@ import copy
 import json
 import logging
 from json import JSONDecodeError
-from typing import Annotated, Any, Optional
+from typing import Any, Optional
 
-from pydantic import SkipValidation, ValidationError
+from pydantic import BaseModel, SkipValidation, ValidationError
 
 from langchain_core.exceptions import OutputParserException
 from langchain_core.messages import AIMessage, InvalidToolCall
@@ -15,7 +15,6 @@ from langchain_core.messages.tool import tool_call as create_tool_call
 from langchain_core.output_parsers.transform import BaseCumulativeTransformOutputParser
 from langchain_core.outputs import ChatGeneration, Generation
 from langchain_core.utils.json import parse_partial_json
-from langchain_core.utils.pydantic import TypeBaseModel
 
 logger = logging.getLogger(__name__)
 
@@ -264,7 +263,7 @@ _MAX_TOKENS_ERROR = (
 class PydanticToolsParser(JsonOutputToolsParser):
     """Parse tools from OpenAI response."""
 
-    tools: Annotated[list[TypeBaseModel], SkipValidation()]
+    tools: SkipValidation[list[type[BaseModel]]]
     """The tools to parse."""
 
     # TODO: Support more granular streaming of objects. Currently only streams once all
diff --git a/libs/core/langchain_core/output_parsers/pydantic.py b/libs/core/langchain_core/output_parsers/pydantic.py
index 194cc3a2d36..05d2eccf385 100644
--- a/libs/core/langchain_core/output_parsers/pydantic.py
+++ b/libs/core/langchain_core/output_parsers/pydantic.py
@@ -1,45 +1,33 @@
 """Output parsers using Pydantic."""
 
 import json
-from typing import Annotated, Generic, Optional
+from typing import Generic, Optional, TypeVar
 
-import pydantic
-from pydantic import SkipValidation
+from pydantic import BaseModel, SkipValidation, ValidationError
 from typing_extensions import override
 
 from langchain_core.exceptions import OutputParserException
 from langchain_core.output_parsers import JsonOutputParser
 from langchain_core.outputs import Generation
-from langchain_core.utils.pydantic import (
-    IS_PYDANTIC_V2,
-    PydanticBaseModel,
-    TBaseModel,
-)
+
+BaseModelT = TypeVar("BaseModelT", bound=BaseModel)
 
 
-class PydanticOutputParser(JsonOutputParser, Generic[TBaseModel]):
+class PydanticOutputParser(JsonOutputParser, Generic[BaseModelT]):
     """Parse an output using a pydantic model."""
 
-    pydantic_object: Annotated[type[TBaseModel], SkipValidation()]
+    pydantic_object: SkipValidation[type[BaseModelT]]
     """The pydantic model to parse."""
 
-    def _parse_obj(self, obj: dict) -> TBaseModel:
-        if IS_PYDANTIC_V2:
-            try:
-                if issubclass(self.pydantic_object, pydantic.BaseModel):
-                    return self.pydantic_object.model_validate(obj)
-                if issubclass(self.pydantic_object, pydantic.v1.BaseModel):
-                    return self.pydantic_object.parse_obj(obj)
-                msg = f"Unsupported model version for PydanticOutputParser: \
-                            {self.pydantic_object.__class__}"
-                raise OutputParserException(msg)
-            except (pydantic.ValidationError, pydantic.v1.ValidationError) as e:
-                raise self._parser_exception(e, obj) from e
-        else:  # pydantic v1
-            try:
-                return self.pydantic_object.parse_obj(obj)
-            except pydantic.ValidationError as e:
-                raise self._parser_exception(e, obj) from e
+    def _parse_obj(self, obj: dict) -> BaseModelT:
+        try:
+            if issubclass(self.pydantic_object, BaseModel):
+                return self.pydantic_object.model_validate(obj)
+            msg = f"Unsupported model version for PydanticOutputParser: \
+                        {self.pydantic_object.__class__}"
+            raise OutputParserException(msg)
+        except ValidationError as e:
+            raise self._parser_exception(e, obj) from e
 
     def _parser_exception(
         self, e: Exception, json_object: dict
@@ -51,7 +39,7 @@ class PydanticOutputParser(JsonOutputParser, Generic[TBaseModel]):
 
     def parse_result(
         self, result: list[Generation], *, partial: bool = False
-    ) -> Optional[TBaseModel]:
+    ) -> Optional[BaseModelT]:
         """Parse the result of an LLM call to a pydantic object.
 
         Args:
@@ -72,7 +60,7 @@ class PydanticOutputParser(JsonOutputParser, Generic[TBaseModel]):
                 return None
             raise
 
-    def parse(self, text: str) -> TBaseModel:
+    def parse(self, text: str) -> BaseModelT:
         """Parse the output of an LLM call to a pydantic object.
 
         Args:
@@ -109,7 +97,7 @@ class PydanticOutputParser(JsonOutputParser, Generic[TBaseModel]):
 
     @property
     @override
-    def OutputType(self) -> type[TBaseModel]:
+    def OutputType(self) -> type[BaseModelT]:
         """Return the pydantic model."""
         return self.pydantic_object
 
@@ -126,7 +114,5 @@ Here is the output schema:
 
 # Re-exporting types for backwards compatibility
 __all__ = [
-    "PydanticBaseModel",
     "PydanticOutputParser",
-    "TBaseModel",
 ]
diff --git a/libs/core/langchain_core/output_parsers/transform.py b/libs/core/langchain_core/output_parsers/transform.py
index 783abedf116..42949bdaf55 100644
--- a/libs/core/langchain_core/output_parsers/transform.py
+++ b/libs/core/langchain_core/output_parsers/transform.py
@@ -125,7 +125,7 @@ class BaseCumulativeTransformOutputParser(BaseTransformOutputParser[T]):
                 chunk_gen = ChatGenerationChunk(message=chunk)
             elif isinstance(chunk, BaseMessage):
                 chunk_gen = ChatGenerationChunk(
-                    message=BaseMessageChunk(**chunk.dict())
+                    message=BaseMessageChunk(**chunk.model_dump())
                 )
             else:
                 chunk_gen = GenerationChunk(text=chunk)
@@ -151,7 +151,7 @@ class BaseCumulativeTransformOutputParser(BaseTransformOutputParser[T]):
                 chunk_gen = ChatGenerationChunk(message=chunk)
             elif isinstance(chunk, BaseMessage):
                 chunk_gen = ChatGenerationChunk(
-                    message=BaseMessageChunk(**chunk.dict())
+                    message=BaseMessageChunk(**chunk.model_dump())
                 )
             else:
                 chunk_gen = GenerationChunk(text=chunk)
diff --git a/libs/core/langchain_core/prompts/base.py b/libs/core/langchain_core/prompts/base.py
index d880971750f..02808488f69 100644
--- a/libs/core/langchain_core/prompts/base.py
+++ b/libs/core/langchain_core/prompts/base.py
@@ -331,7 +331,7 @@ class BasePromptTemplate(
         """Return the prompt type key."""
         raise NotImplementedError
 
-    def dict(self, **kwargs: Any) -> dict:
+    def model_dump(self, **kwargs: Any) -> dict:
         """Return dictionary representation of prompt.
 
         Args:
@@ -369,7 +369,7 @@ class BasePromptTemplate(
             raise ValueError(msg)
 
         # Fetch dictionary to save
-        prompt_dict = self.dict()
+        prompt_dict = self.model_dump()
         if "_type" not in prompt_dict:
             msg = f"Prompt {self} does not support saving."
             raise NotImplementedError(msg)
diff --git a/libs/core/langchain_core/prompts/chat.py b/libs/core/langchain_core/prompts/chat.py
index b80954336c5..11cfe14f8cc 100644
--- a/libs/core/langchain_core/prompts/chat.py
+++ b/libs/core/langchain_core/prompts/chat.py
@@ -6,7 +6,6 @@ from abc import ABC, abstractmethod
 from pathlib import Path
 from typing import (
     TYPE_CHECKING,
-    Annotated,
     Any,
     Optional,
     TypedDict,
@@ -886,7 +885,7 @@ class ChatPromptTemplate(BaseChatPromptTemplate):
 
     """  # noqa: E501
 
-    messages: Annotated[list[MessageLike], SkipValidation()]
+    messages: SkipValidation[list[MessageLike]]
     """List of messages consisting of either message prompt templates or messages."""
     validate_template: bool = False
     """Whether or not to try validating the template."""
diff --git a/libs/core/langchain_core/prompts/string.py b/libs/core/langchain_core/prompts/string.py
index e63d54dbbde..c1098aa2b51 100644
--- a/libs/core/langchain_core/prompts/string.py
+++ b/libs/core/langchain_core/prompts/string.py
@@ -98,7 +98,7 @@ def _get_jinja2_variables_from_template(template: str) -> set[str]:
         raise ImportError(msg) from e
     env = Environment()  # noqa: S701
     ast = env.parse(template)
-    return meta.find_undeclared_variables(ast)
+    return meta.find_undeclared_variables(ast)  # type: ignore[no-untyped-call]
 
 
 def mustache_formatter(template: str, /, **kwargs: Any) -> str:
diff --git a/libs/core/langchain_core/pydantic_v1/__init__.py b/libs/core/langchain_core/pydantic_v1/__init__.py
deleted file mode 100644
index e4dfbbaea19..00000000000
--- a/libs/core/langchain_core/pydantic_v1/__init__.py
+++ /dev/null
@@ -1,45 +0,0 @@
-"""Pydantic v1 compatibility shim."""
-
-from importlib import metadata
-
-from langchain_core._api.deprecation import warn_deprecated
-
-# Create namespaces for pydantic v1 and v2.
-# This code must stay at the top of the file before other modules may
-# attempt to import pydantic since it adds pydantic_v1 and pydantic_v2 to sys.modules.
-#
-# This hack is done for the following reasons:
-# * Langchain will attempt to remain compatible with both pydantic v1 and v2 since
-#   both dependencies and dependents may be stuck on either version of v1 or v2.
-# * Creating namespaces for pydantic v1 and v2 should allow us to write code that
-#   unambiguously uses either v1 or v2 API.
-# * This change is easier to roll out and roll back.
-
-try:
-    from pydantic.v1 import *  # noqa: F403
-except ImportError:
-    from pydantic import *  # type: ignore[assignment,no-redef] # noqa: F403
-
-
-try:
-    _PYDANTIC_MAJOR_VERSION: int = int(metadata.version("pydantic").split(".")[0])
-except metadata.PackageNotFoundError:
-    _PYDANTIC_MAJOR_VERSION = 0
-
-warn_deprecated(
-    "0.3.0",
-    removal="1.0.0",
-    alternative="pydantic.v1 or pydantic",
-    message=(
-        "As of langchain-core 0.3.0, LangChain uses pydantic v2 internally. "
-        "The langchain_core.pydantic_v1 module was a "
-        "compatibility shim for pydantic v1, and should no longer be used. "
-        "Please update the code to import from Pydantic directly.\n\n"
-        "For example, replace imports like: "
-        "`from langchain_core.pydantic_v1 import BaseModel`\n"
-        "with: `from pydantic import BaseModel`\n"
-        "or the v1 compatibility namespace if you are working in a code base "
-        "that has not been fully upgraded to pydantic 2 yet. "
-        "\tfrom pydantic.v1 import BaseModel\n"
-    ),
-)
diff --git a/libs/core/langchain_core/pydantic_v1/dataclasses.py b/libs/core/langchain_core/pydantic_v1/dataclasses.py
deleted file mode 100644
index 812660578bd..00000000000
--- a/libs/core/langchain_core/pydantic_v1/dataclasses.py
+++ /dev/null
@@ -1,26 +0,0 @@
-"""Pydantic v1 compatibility shim."""
-
-from langchain_core._api import warn_deprecated
-
-try:
-    from pydantic.v1.dataclasses import *  # noqa: F403
-except ImportError:
-    from pydantic.dataclasses import *  # type: ignore[no-redef] # noqa: F403
-
-warn_deprecated(
-    "0.3.0",
-    removal="1.0.0",
-    alternative="pydantic.v1 or pydantic",
-    message=(
-        "As of langchain-core 0.3.0, LangChain uses pydantic v2 internally. "
-        "The langchain_core.pydantic_v1 module was a "
-        "compatibility shim for pydantic v1, and should no longer be used. "
-        "Please update the code to import from Pydantic directly.\n\n"
-        "For example, replace imports like: "
-        "`from langchain_core.pydantic_v1 import BaseModel`\n"
-        "with: `from pydantic import BaseModel`\n"
-        "or the v1 compatibility namespace if you are working in a code base "
-        "that has not been fully upgraded to pydantic 2 yet. "
-        "\tfrom pydantic.v1 import BaseModel\n"
-    ),
-)
diff --git a/libs/core/langchain_core/pydantic_v1/main.py b/libs/core/langchain_core/pydantic_v1/main.py
deleted file mode 100644
index 88492823173..00000000000
--- a/libs/core/langchain_core/pydantic_v1/main.py
+++ /dev/null
@@ -1,26 +0,0 @@
-"""Pydantic v1 compatibility shim."""
-
-from langchain_core._api import warn_deprecated
-
-try:
-    from pydantic.v1.main import *  # noqa: F403
-except ImportError:
-    from pydantic.main import *  # type: ignore[assignment,no-redef] # noqa: F403
-
-warn_deprecated(
-    "0.3.0",
-    removal="1.0.0",
-    alternative="pydantic.v1 or pydantic",
-    message=(
-        "As of langchain-core 0.3.0, LangChain uses pydantic v2 internally. "
-        "The langchain_core.pydantic_v1 module was a "
-        "compatibility shim for pydantic v1, and should no longer be used. "
-        "Please update the code to import from Pydantic directly.\n\n"
-        "For example, replace imports like: "
-        "`from langchain_core.pydantic_v1 import BaseModel`\n"
-        "with: `from pydantic import BaseModel`\n"
-        "or the v1 compatibility namespace if you are working in a code base "
-        "that has not been fully upgraded to pydantic 2 yet. "
-        "\tfrom pydantic.v1 import BaseModel\n"
-    ),
-)
diff --git a/libs/core/langchain_core/runnables/graph.py b/libs/core/langchain_core/runnables/graph.py
index 323dcdd2d48..ddc29a3dfd6 100644
--- a/libs/core/langchain_core/runnables/graph.py
+++ b/libs/core/langchain_core/runnables/graph.py
@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import inspect
 from collections import defaultdict
 from dataclasses import dataclass, field
 from enum import Enum
@@ -19,13 +18,13 @@ from typing import (
 )
 from uuid import UUID, uuid4
 
-from langchain_core.utils.pydantic import _IgnoreUnserializable, is_basemodel_subclass
+from pydantic import BaseModel
+
+from langchain_core.utils.pydantic import _IgnoreUnserializable
 
 if TYPE_CHECKING:
     from collections.abc import Sequence
 
-    from pydantic import BaseModel
-
     from langchain_core.runnables.base import Runnable as RunnableType
 
 
@@ -233,7 +232,7 @@ def node_data_json(
                 "name": node_data_str(node.id, node.data),
             },
         }
-    elif inspect.isclass(node.data) and is_basemodel_subclass(node.data):
+    elif isinstance(node.data, type) and issubclass(node.data, BaseModel):
         json = (
             {
                 "type": "schema",
diff --git a/libs/core/langchain_core/tools/base.py b/libs/core/langchain_core/tools/base.py
index 52123ec6b4f..ca8454664c4 100644
--- a/libs/core/langchain_core/tools/base.py
+++ b/libs/core/langchain_core/tools/base.py
@@ -33,9 +33,6 @@ from pydantic import (
     model_validator,
     validate_arguments,
 )
-from pydantic.v1 import BaseModel as BaseModelV1
-from pydantic.v1 import ValidationError as ValidationErrorV1
-from pydantic.v1 import validate_arguments as validate_arguments_v1
 from typing_extensions import override
 
 from langchain_core._api import deprecated
@@ -59,14 +56,7 @@ from langchain_core.utils.function_calling import (
     _parse_google_docstring,
     _py_38_safe_origin,
 )
-from langchain_core.utils.pydantic import (
-    TypeBaseModel,
-    _create_subset_model,
-    get_fields,
-    is_basemodel_subclass,
-    is_pydantic_v1_subclass,
-    is_pydantic_v2_subclass,
-)
+from langchain_core.utils.pydantic import _create_subset_model, get_fields
 
 if TYPE_CHECKING:
     import uuid
@@ -165,36 +155,6 @@ def _infer_arg_descriptions(
     return description, arg_descriptions
 
 
-def _is_pydantic_annotation(annotation: Any, pydantic_version: str = "v2") -> bool:
-    """Determine if a type annotation is a Pydantic model."""
-    base_model_class = BaseModelV1 if pydantic_version == "v1" else BaseModel
-    try:
-        return issubclass(annotation, base_model_class)
-    except TypeError:
-        return False
-
-
-def _function_annotations_are_pydantic_v1(
-    signature: inspect.Signature, func: Callable
-) -> bool:
-    """Determine if all Pydantic annotations in a function signature are from V1."""
-    any_v1_annotations = any(
-        _is_pydantic_annotation(parameter.annotation, pydantic_version="v1")
-        for parameter in signature.parameters.values()
-    )
-    any_v2_annotations = any(
-        _is_pydantic_annotation(parameter.annotation, pydantic_version="v2")
-        for parameter in signature.parameters.values()
-    )
-    if any_v1_annotations and any_v2_annotations:
-        msg = (
-            f"Function {func} contains a mix of Pydantic v1 and v2 annotations. "
-            "Only one version of Pydantic annotations per function is supported."
-        )
-        raise NotImplementedError(msg)
-    return any_v1_annotations and not any_v2_annotations
-
-
 class _SchemaConfig:
     """Configuration for the pydantic model.
 
@@ -241,16 +201,13 @@ def create_schema_from_function(
     """
     sig = inspect.signature(func)
 
-    if _function_annotations_are_pydantic_v1(sig, func):
-        validated = validate_arguments_v1(func, config=_SchemaConfig)  # type: ignore[call-overload]
-    else:
-        # https://docs.pydantic.dev/latest/usage/validation_decorator/
-        with warnings.catch_warnings():
-            # We are using deprecated functionality here.
-            # This code should be re-written to simply construct a pydantic model
-            # using inspect.signature and create_model.
-            warnings.simplefilter("ignore", category=PydanticDeprecationWarning)
-            validated = validate_arguments(func, config=_SchemaConfig)  # type: ignore[operator]
+    # https://docs.pydantic.dev/latest/usage/validation_decorator/
+    with warnings.catch_warnings():
+        # We are using deprecated functionality here.
+        # This code should be re-written to simply construct a pydantic model
+        # using inspect.signature and create_model.
+        warnings.simplefilter("ignore", category=PydanticDeprecationWarning)
+        validated = validate_arguments(func, config=_SchemaConfig)  # type: ignore[operator]
 
     # Let's ignore `self` and `cls` arguments for class and instance methods
     # If qualified name has a ".", then it likely belongs in a class namespace
@@ -321,7 +278,7 @@ class ToolException(Exception):  # noqa: N818
     """
 
 
-ArgsSchema = Union[TypeBaseModel, dict[str, Any]]
+ArgsSchema = Union[type[BaseModel], dict[str, Any]]
 
 
 class BaseTool(RunnableSerializable[Union[str, dict, ToolCall], Any]):
@@ -361,7 +318,7 @@ class ChildTool(BaseTool):
     You can provide few-shot examples as a part of the description.
     """
 
-    args_schema: Annotated[Optional[ArgsSchema], SkipValidation()] = Field(
+    args_schema: SkipValidation[Optional[ArgsSchema]] = Field(
         default=None, description="The tool schema."
     )
     """Pydantic model class to validate and parse the tool's input arguments.
@@ -370,8 +327,6 @@ class ChildTool(BaseTool):
 
     - A subclass of pydantic.BaseModel.
     or
-    - A subclass of pydantic.v1.BaseModel if accessing v1 namespace in pydantic 2
-    or
     - a JSON schema dict
     """
     return_direct: bool = False
@@ -414,7 +369,7 @@ class ChildTool(BaseTool):
     """Handle the content of the ToolException thrown."""
 
     handle_validation_error: Optional[
-        Union[bool, str, Callable[[Union[ValidationError, ValidationErrorV1]], str]]
+        Union[bool, str, Callable[[ValidationError], str]]
     ] = False
     """Handle the content of the ValidationError thrown."""
 
@@ -431,7 +386,7 @@ class ChildTool(BaseTool):
         if (
             "args_schema" in kwargs
             and kwargs["args_schema"] is not None
-            and not is_basemodel_subclass(kwargs["args_schema"])
+            and not issubclass(kwargs["args_schema"], BaseModel)
             and not isinstance(kwargs["args_schema"], dict)
         ):
             msg = (
@@ -543,10 +498,7 @@ class ChildTool(BaseTool):
                     )
                     raise ValueError(msg)
                 key_ = next(iter(get_fields(input_args).keys()))
-                if hasattr(input_args, "model_validate"):
-                    input_args.model_validate({key_: tool_input})
-                else:
-                    input_args.parse_obj({key_: tool_input})
+                input_args.model_validate({key_: tool_input})
             return tool_input
         if input_args is not None:
             if isinstance(input_args, dict):
@@ -569,24 +521,6 @@ class ChildTool(BaseTool):
                         tool_input[k] = tool_call_id
                 result = input_args.model_validate(tool_input)
                 result_dict = result.model_dump()
-            elif issubclass(input_args, BaseModelV1):
-                for k, v in get_all_basemodel_annotations(input_args).items():
-                    if (
-                        _is_injected_arg_type(v, injected_type=InjectedToolCallId)
-                        and k not in tool_input
-                    ):
-                        if tool_call_id is None:
-                            msg = (
-                                "When tool includes an InjectedToolCallId "
-                                "argument, tool must always be invoked with a full "
-                                "model ToolCall of the form: {'args': {...}, "
-                                "'name': '...', 'type': 'tool_call', "
-                                "'tool_call_id': '...'}"
-                            )
-                            raise ValueError(msg)
-                        tool_input[k] = tool_call_id
-                result = input_args.parse_obj(tool_input)
-                result_dict = result.dict()
             else:
                 msg = (
                     f"args_schema must be a Pydantic BaseModel, got {self.args_schema}"
@@ -643,7 +577,7 @@ class ChildTool(BaseTool):
         if (
             self.args_schema is not None
             and isinstance(self.args_schema, type)
-            and is_basemodel_subclass(self.args_schema)
+            and issubclass(self.args_schema, BaseModel)
             and not get_fields(self.args_schema)
         ):
             # StructuredTool with no args
@@ -754,7 +688,7 @@ class ChildTool(BaseTool):
                     content, artifact = response
             else:
                 content = response
-        except (ValidationError, ValidationErrorV1) as e:
+        except ValidationError as e:
             if not self.handle_validation_error:
                 error_to_raise = e
             else:
@@ -901,11 +835,9 @@ def _is_tool_call(x: Any) -> bool:
 
 
 def _handle_validation_error(
-    e: Union[ValidationError, ValidationErrorV1],
+    e: ValidationError,
     *,
-    flag: Union[
-        Literal[True], str, Callable[[Union[ValidationError, ValidationErrorV1]], str]
-    ],
+    flag: Union[Literal[True], str, Callable[[ValidationError], str]],
 ) -> str:
     if isinstance(flag, bool):
         content = "Tool input validation error"
@@ -1067,7 +999,7 @@ def _is_injected_arg_type(
 
 
 def get_all_basemodel_annotations(
-    cls: Union[TypeBaseModel, Any], *, default_to_bound: bool = True
+    cls: type[BaseModel], *, default_to_bound: bool = True
 ) -> dict[str, type]:
     """Get all annotations from a Pydantic BaseModel and its parents.
 
@@ -1075,58 +1007,17 @@ def get_all_basemodel_annotations(
         cls: The Pydantic BaseModel class.
         default_to_bound: Whether to default to the bound of a TypeVar if it exists.
     """
-    # cls has no subscript: cls = FooBar
-    if isinstance(cls, type):
-        # Gather pydantic field objects (v2: model_fields / v1: __fields__)
-        fields = getattr(cls, "model_fields", {}) or getattr(cls, "__fields__", {})
-        alias_map = {field.alias: name for name, field in fields.items() if field.alias}
+    fields = cls.model_fields
+    alias_map = {field.alias: name for name, field in fields.items() if field.alias}
 
-        annotations: dict[str, type] = {}
-        for name, param in inspect.signature(cls).parameters.items():
-            # Exclude hidden init args added by pydantic Config. For example if
-            # BaseModel(extra="allow") then "extra_data" will part of init sig.
-            if fields and name not in fields and name not in alias_map:
-                continue
-            field_name = alias_map.get(name, name)
-            annotations[field_name] = param.annotation
-        orig_bases: tuple = getattr(cls, "__orig_bases__", ())
-    # cls has subscript: cls = FooBar[int]
-    else:
-        annotations = get_all_basemodel_annotations(
-            get_origin(cls), default_to_bound=False
-        )
-        orig_bases = (cls,)
-
-    # Pydantic v2 automatically resolves inherited generics, Pydantic v1 does not.
-    if not (isinstance(cls, type) and is_pydantic_v2_subclass(cls)):
-        # if cls = FooBar inherits from Baz[str], orig_bases will contain Baz[str]
-        # if cls = FooBar inherits from Baz, orig_bases will contain Baz
-        # if cls = FooBar[int], orig_bases will contain FooBar[int]
-        for parent in orig_bases:
-            # if class = FooBar inherits from Baz, parent = Baz
-            if isinstance(parent, type) and is_pydantic_v1_subclass(parent):
-                annotations.update(
-                    get_all_basemodel_annotations(parent, default_to_bound=False)
-                )
-                continue
-
-            parent_origin = get_origin(parent)
-
-            # if class = FooBar inherits from non-pydantic class
-            if not parent_origin:
-                continue
-
-            # if class = FooBar inherits from Baz[str]:
-            # parent = Baz[str],
-            # parent_origin = Baz,
-            # generic_type_vars = (type vars in Baz)
-            # generic_map = {type var in Baz: str}
-            generic_type_vars: tuple = getattr(parent_origin, "__parameters__", ())
-            generic_map = dict(zip(generic_type_vars, get_args(parent)))
-            for field in getattr(parent_origin, "__annotations__", {}):
-                annotations[field] = _replace_type_vars(
-                    annotations[field], generic_map, default_to_bound=default_to_bound
-                )
+    annotations: dict[str, type] = {}
+    for name, param in inspect.signature(cls).parameters.items():
+        # Exclude hidden init args added by pydantic's ConfigDict. For example if
+        # BaseModel(extra="allow") then "extra_data" will part of init sig.
+        if fields and name not in fields and name not in alias_map:
+            continue
+        field_name = alias_map.get(name, name)
+        annotations[field_name] = param.annotation
 
     return {
         k: _replace_type_vars(v, default_to_bound=default_to_bound)
diff --git a/libs/core/langchain_core/tools/structured.py b/libs/core/langchain_core/tools/structured.py
index 4e202dfea3a..ddb2bbe626c 100644
--- a/libs/core/langchain_core/tools/structured.py
+++ b/libs/core/langchain_core/tools/structured.py
@@ -7,7 +7,6 @@ from collections.abc import Awaitable
 from inspect import signature
 from typing import (
     TYPE_CHECKING,
-    Annotated,
     Any,
     Callable,
     Literal,
@@ -15,7 +14,7 @@ from typing import (
     Union,
 )
 
-from pydantic import Field, SkipValidation
+from pydantic import BaseModel, Field, SkipValidation
 from typing_extensions import override
 
 from langchain_core.callbacks import (
@@ -30,7 +29,6 @@ from langchain_core.tools.base import (
     _get_runnable_config_param,
     create_schema_from_function,
 )
-from langchain_core.utils.pydantic import is_basemodel_subclass
 
 if TYPE_CHECKING:
     from langchain_core.messages import ToolCall
@@ -40,9 +38,7 @@ class StructuredTool(BaseTool):
     """Tool that can operate on any number of inputs."""
 
     description: str = ""
-    args_schema: Annotated[ArgsSchema, SkipValidation()] = Field(
-        ..., description="The tool schema."
-    )
+    args_schema: SkipValidation[ArgsSchema] = Field(..., description="The tool schema.")
     """The input arguments' schema."""
     func: Optional[Callable[..., Any]] = None
     """The function to run when the tool is called."""
@@ -196,7 +192,7 @@ class StructuredTool(BaseTool):
         if description is None and not parse_docstring:
             description_ = source_function.__doc__ or None
         if description_ is None and args_schema:
-            if isinstance(args_schema, type) and is_basemodel_subclass(args_schema):
+            if isinstance(args_schema, type) and issubclass(args_schema, BaseModel):
                 description_ = args_schema.__doc__ or None
             elif isinstance(args_schema, dict):
                 description_ = args_schema.get("description")
diff --git a/libs/core/langchain_core/tracers/schemas.py b/libs/core/langchain_core/tracers/schemas.py
index e7ebad1da1e..ea06cb2f9dc 100644
--- a/libs/core/langchain_core/tracers/schemas.py
+++ b/libs/core/langchain_core/tracers/schemas.py
@@ -2,8 +2,8 @@
 
 from __future__ import annotations
 
-import datetime
 import warnings
+from datetime import datetime, timezone
 from typing import Any, Optional
 from uuid import UUID
 
@@ -32,7 +32,7 @@ def RunTypeEnum() -> type[RunTypeEnumDep]:  # noqa: N802
 class TracerSessionV1Base(BaseModelV1):
     """Base class for TracerSessionV1."""
 
-    start_time: datetime.datetime = FieldV1(default_factory=datetime.datetime.utcnow)
+    start_time: datetime = FieldV1(default_factory=lambda: datetime.now(timezone.utc))
     name: Optional[str] = None
     extra: Optional[dict[str, Any]] = None
 
@@ -69,8 +69,8 @@ class BaseRun(BaseModelV1):
 
     uuid: str
     parent_uuid: Optional[str] = None
-    start_time: datetime.datetime = FieldV1(default_factory=datetime.datetime.utcnow)
-    end_time: datetime.datetime = FieldV1(default_factory=datetime.datetime.utcnow)
+    start_time: datetime = FieldV1(default_factory=lambda: datetime.now(timezone.utc))
+    end_time: datetime = FieldV1(default_factory=lambda: datetime.now(timezone.utc))
     extra: Optional[dict[str, Any]] = None
     execution_order: int
     child_execution_order: int
diff --git a/libs/core/langchain_core/utils/function_calling.py b/libs/core/langchain_core/utils/function_calling.py
index bfc70df1715..8f5512c0914 100644
--- a/libs/core/langchain_core/utils/function_calling.py
+++ b/libs/core/langchain_core/utils/function_calling.py
@@ -20,13 +20,11 @@ from typing import (
 )
 
 from pydantic import BaseModel
-from pydantic.v1 import BaseModel as BaseModelV1
 from typing_extensions import TypedDict, get_args, get_origin, is_typeddict
 
 from langchain_core._api import beta, deprecated
 from langchain_core.messages import AIMessage, BaseMessage, HumanMessage, ToolMessage
 from langchain_core.utils.json_schema import dereference_refs
-from langchain_core.utils.pydantic import is_basemodel_subclass
 
 if TYPE_CHECKING:
     from langchain_core.tools import BaseTool
@@ -150,9 +148,7 @@ def _convert_pydantic_to_openai_function(
         The function description.
     """
     if hasattr(model, "model_json_schema"):
-        schema = model.model_json_schema()  # Pydantic 2
-    elif hasattr(model, "schema"):
-        schema = model.schema()  # Pydantic 1
+        schema = model.model_json_schema()
     else:
         msg = "Model must be a Pydantic model."
         raise TypeError(msg)
@@ -249,6 +245,7 @@ def _convert_typed_dict_to_openai_function(typed_dict: type) -> FunctionDescript
         "type[BaseModel]",
         _convert_any_typed_dicts_to_pydantic(typed_dict, visited=visited),
     )
+    print(model)
     return _convert_pydantic_to_openai_function(model)
 
 
@@ -336,7 +333,7 @@ def _format_tool_to_openai_function(tool: BaseTool) -> FunctionDescription:
             return _convert_json_schema_to_openai_function(
                 tool.tool_call_schema, name=tool.name, description=tool.description
             )
-        if issubclass(tool.tool_call_schema, (BaseModel, BaseModelV1)):
+        if issubclass(tool.tool_call_schema, BaseModel):
             return _convert_pydantic_to_openai_function(
                 tool.tool_call_schema, name=tool.name, description=tool.description
             )
@@ -466,7 +463,7 @@ def convert_to_openai_function(
             oai_function["description"] = function_copy.pop("description")
         if function_copy and "properties" in function_copy:
             oai_function["parameters"] = function_copy
-    elif isinstance(function, type) and is_basemodel_subclass(function):
+    elif isinstance(function, type) and issubclass(function, BaseModel):
         oai_function = cast("dict", _convert_pydantic_to_openai_function(function))
     elif is_typeddict(function):
         oai_function = cast(
diff --git a/libs/core/langchain_core/utils/pydantic.py b/libs/core/langchain_core/utils/pydantic.py
index ea987741ce3..8ec8d64dbe5 100644
--- a/libs/core/langchain_core/utils/pydantic.py
+++ b/libs/core/langchain_core/utils/pydantic.py
@@ -2,173 +2,39 @@
 
 from __future__ import annotations
 
-import inspect
 import textwrap
 import warnings
 from contextlib import nullcontext
 from functools import lru_cache, wraps
-from types import GenericAlias
 from typing import (
     TYPE_CHECKING,
     Any,
     Callable,
     Optional,
-    TypeVar,
-    Union,
     cast,
-    overload,
 )
 
-import pydantic
 from packaging import version
-from pydantic import (
-    BaseModel,
-    ConfigDict,
-    PydanticDeprecationWarning,
-    RootModel,
-    root_validator,
-)
+from pydantic import BaseModel, ConfigDict, Field, RootModel, model_validator
 from pydantic import (
     create_model as _create_model_base,
 )
-from pydantic.fields import FieldInfo as FieldInfoV2
+from pydantic.fields import FieldInfo
 from pydantic.json_schema import (
     DEFAULT_REF_TEMPLATE,
     GenerateJsonSchema,
     JsonSchemaMode,
     JsonSchemaValue,
 )
+from pydantic.version import VERSION as PYDANTIC_VERSION_STRING
 from typing_extensions import override
 
 if TYPE_CHECKING:
     from pydantic_core import core_schema
 
-try:
-    import pydantic
-
-    PYDANTIC_VERSION = version.parse(pydantic.__version__)
-except ImportError:
-    PYDANTIC_VERSION = version.parse("0.0.0")
-
-
-def get_pydantic_major_version() -> int:
-    """DEPRECATED - Get the major version of Pydantic.
-
-    Use PYDANTIC_VERSION.major instead.
-    """
-    warnings.warn(
-        "get_pydantic_major_version is deprecated. Use PYDANTIC_VERSION.major instead.",
-        DeprecationWarning,
-        stacklevel=2,
-    )
-    return PYDANTIC_VERSION.major
-
-
-PYDANTIC_MAJOR_VERSION = PYDANTIC_VERSION.major
+PYDANTIC_VERSION = version.parse(PYDANTIC_VERSION_STRING)
 PYDANTIC_MINOR_VERSION = PYDANTIC_VERSION.minor
 
-IS_PYDANTIC_V1 = PYDANTIC_VERSION.major == 1
-IS_PYDANTIC_V2 = PYDANTIC_VERSION.major == 2
-
-if IS_PYDANTIC_V1:
-    from pydantic.fields import FieldInfo as FieldInfoV1
-
-    PydanticBaseModel = pydantic.BaseModel
-    TypeBaseModel = type[BaseModel]
-elif IS_PYDANTIC_V2:
-    from pydantic.v1.fields import FieldInfo as FieldInfoV1  # type: ignore[assignment]
-
-    # Union type needs to be last assignment to PydanticBaseModel to make mypy happy.
-    PydanticBaseModel = Union[BaseModel, pydantic.BaseModel]  # type: ignore[assignment,misc]
-    TypeBaseModel = Union[type[BaseModel], type[pydantic.BaseModel]]  # type: ignore[misc]
-else:
-    msg = f"Unsupported Pydantic version: {PYDANTIC_VERSION.major}"
-    raise ValueError(msg)
-
-
-TBaseModel = TypeVar("TBaseModel", bound=PydanticBaseModel)
-
-
-def is_pydantic_v1_subclass(cls: type) -> bool:
-    """Check if the installed Pydantic version is 1.x-like."""
-    if IS_PYDANTIC_V1:
-        return True
-    if IS_PYDANTIC_V2:
-        from pydantic.v1 import BaseModel as BaseModelV1
-
-        if issubclass(cls, BaseModelV1):
-            return True
-    return False
-
-
-def is_pydantic_v2_subclass(cls: type) -> bool:
-    """Check if the installed Pydantic version is 1.x-like."""
-    from pydantic import BaseModel
-
-    return IS_PYDANTIC_V2 and issubclass(cls, BaseModel)
-
-
-def is_basemodel_subclass(cls: type) -> bool:
-    """Check if the given class is a subclass of Pydantic BaseModel.
-
-    Check if the given class is a subclass of any of the following:
-
-    * pydantic.BaseModel in Pydantic 1.x
-    * pydantic.BaseModel in Pydantic 2.x
-    * pydantic.v1.BaseModel in Pydantic 2.x
-    """
-    # Before we can use issubclass on the cls we need to check if it is a class
-    if not inspect.isclass(cls) or isinstance(cls, GenericAlias):
-        return False
-
-    if IS_PYDANTIC_V1:
-        from pydantic import BaseModel as BaseModelV1Proper
-
-        if issubclass(cls, BaseModelV1Proper):
-            return True
-    elif IS_PYDANTIC_V2:
-        from pydantic import BaseModel as BaseModelV2
-        from pydantic.v1 import BaseModel as BaseModelV1
-
-        if issubclass(cls, BaseModelV2):
-            return True
-
-        if issubclass(cls, BaseModelV1):
-            return True
-    else:
-        msg = f"Unsupported Pydantic version: {PYDANTIC_VERSION.major}"
-        raise ValueError(msg)
-    return False
-
-
-def is_basemodel_instance(obj: Any) -> bool:
-    """Check if the given class is an instance of Pydantic BaseModel.
-
-    Check if the given class is an instance of any of the following:
-
-    * pydantic.BaseModel in Pydantic 1.x
-    * pydantic.BaseModel in Pydantic 2.x
-    * pydantic.v1.BaseModel in Pydantic 2.x
-    """
-    if IS_PYDANTIC_V1:
-        from pydantic import BaseModel as BaseModelV1Proper
-
-        if isinstance(obj, BaseModelV1Proper):
-            return True
-    elif IS_PYDANTIC_V2:
-        from pydantic import BaseModel as BaseModelV2
-        from pydantic.v1 import BaseModel as BaseModelV1
-
-        if isinstance(obj, BaseModelV2):
-            return True
-
-        if isinstance(obj, BaseModelV1):
-            return True
-    else:
-        msg = f"Unsupported Pydantic version: {PYDANTIC_VERSION.major}"
-        raise ValueError(msg)
-    return False
-
 
 # How to type hint this?
 def pre_init(func: Callable) -> Any:
@@ -180,50 +46,35 @@ def pre_init(func: Callable) -> Any:
     Returns:
         Any: The decorated function.
     """
-    with warnings.catch_warnings():
-        warnings.filterwarnings(action="ignore", category=PydanticDeprecationWarning)
 
-        @root_validator(pre=True)
-        @wraps(func)
-        def wrapper(cls: type[BaseModel], values: dict[str, Any]) -> dict[str, Any]:
-            """Decorator to run a function before model initialization.
+    @model_validator(mode="before")
+    @wraps(func)
+    def wrapper(cls: type[BaseModel], values: dict[str, Any]) -> dict[str, Any]:
+        """Decorator to run a function before model initialization.
 
-            Args:
-                cls (Type[BaseModel]): The model class.
-                values (dict[str, Any]): The values to initialize the model with.
+        Args:
+            cls (Type[BaseModel]): The model class.
+            values (dict[str, Any]): The values to initialize the model with.
 
-            Returns:
-                dict[str, Any]: The values to initialize the model with.
-            """
-            # Insert default values
-            fields = cls.model_fields
-            for name, field_info in fields.items():
-                # Check if allow_population_by_field_name is enabled
-                # If yes, then set the field name to the alias
-                if (
-                    hasattr(cls, "Config")
-                    and hasattr(cls.Config, "allow_population_by_field_name")
-                    and cls.Config.allow_population_by_field_name
-                    and field_info.alias in values
-                ):
-                    values[name] = values.pop(field_info.alias)
-                if (
-                    hasattr(cls, "model_config")
-                    and cls.model_config.get("populate_by_name")
-                    and field_info.alias in values
-                ):
-                    values[name] = values.pop(field_info.alias)
+        Returns:
+            dict[str, Any]: The values to initialize the model with.
+        """
+        # Insert default values
+        fields = cls.model_fields
+        for name, field_info in fields.items():
+            if cls.model_config.get("populate_by_name") and field_info.alias in values:
+                values[name] = values.pop(field_info.alias)
 
-                if (
-                    name not in values or values[name] is None
-                ) and not field_info.is_required():
-                    if field_info.default_factory is not None:
-                        values[name] = field_info.default_factory()  # type: ignore[call-arg]
-                    else:
-                        values[name] = field_info.default
+            if (
+                name not in values or values[name] is None
+            ) and not field_info.is_required():
+                if field_info.default_factory is not None:
+                    values[name] = field_info.default_factory()  # type: ignore[call-arg]
+                else:
+                    values[name] = field_info.default
 
-            # Call the decorated function
-            return func(cls, values)
+        # Call the decorated function
+        return func(cls, values)
 
     return wrapper
 
@@ -241,55 +92,15 @@ class _IgnoreUnserializable(GenerateJsonSchema):
         return {}
 
 
-def _create_subset_model_v1(
-    name: str,
-    model: type[BaseModel],
-    field_names: list,
-    *,
-    descriptions: Optional[dict] = None,
-    fn_description: Optional[str] = None,
-) -> type[BaseModel]:
-    """Create a pydantic model with only a subset of model's fields."""
-    if IS_PYDANTIC_V1:
-        from pydantic import create_model
-    elif IS_PYDANTIC_V2:
-        from pydantic.v1 import create_model  # type: ignore[no-redef]
-    else:
-        msg = f"Unsupported pydantic version: {PYDANTIC_VERSION.major}"
-        raise NotImplementedError(msg)
-
-    fields = {}
-
-    for field_name in field_names:
-        # Using pydantic v1 so can access __fields__ as a dict.
-        field = model.__fields__[field_name]  # type: ignore[index]
-        t = (
-            # this isn't perfect but should work for most functions
-            field.outer_type_
-            if field.required and not field.allow_none
-            else Optional[field.outer_type_]
-        )
-        if descriptions and field_name in descriptions:
-            field.field_info.description = descriptions[field_name]
-        fields[field_name] = (t, field.field_info)
-
-    rtn = create_model(name, **fields)  # type: ignore[call-overload]
-    rtn.__doc__ = textwrap.dedent(fn_description or model.__doc__ or "")
-    return rtn
-
-
 def _create_subset_model_v2(
     name: str,
-    model: type[pydantic.BaseModel],
+    model: type[BaseModel],
     field_names: list[str],
     *,
     descriptions: Optional[dict] = None,
     fn_description: Optional[str] = None,
-) -> type[pydantic.BaseModel]:
+) -> type[BaseModel]:
     """Create a pydantic model with a subset of the model fields."""
-    from pydantic import create_model
-    from pydantic.fields import FieldInfo
-
     descriptions_ = descriptions or {}
     fields = {}
     for field_name in field_names:
@@ -300,7 +111,7 @@ def _create_subset_model_v2(
             field_info.metadata = field.metadata
         fields[field_name] = (field.annotation, field_info)
 
-    rtn = create_model(  # type: ignore[call-overload]
+    rtn = _create_model_base(
         name, **fields, __config__=ConfigDict(arbitrary_types_allowed=True)
     )
 
@@ -319,89 +130,34 @@ def _create_subset_model_v2(
     return rtn
 
 
-# Private functionality to create a subset model that's compatible across
-# different versions of pydantic.
-# Handles pydantic versions 1.x and 2.x. including v1 of pydantic in 2.x.
-# However, can't find a way to type hint this.
 def _create_subset_model(
     name: str,
-    model: TypeBaseModel,
+    model: type[BaseModel],
     field_names: list[str],
     *,
     descriptions: Optional[dict] = None,
     fn_description: Optional[str] = None,
 ) -> type[BaseModel]:
     """Create subset model using the same pydantic version as the input model."""
-    if IS_PYDANTIC_V1:
-        return _create_subset_model_v1(
-            name,
-            model,
-            field_names,
-            descriptions=descriptions,
-            fn_description=fn_description,
-        )
-    if IS_PYDANTIC_V2:
-        from pydantic.v1 import BaseModel as BaseModelV1
-
-        if issubclass(model, BaseModelV1):
-            return _create_subset_model_v1(
-                name,
-                model,
-                field_names,
-                descriptions=descriptions,
-                fn_description=fn_description,
-            )
-        return _create_subset_model_v2(
-            name,
-            model,
-            field_names,
-            descriptions=descriptions,
-            fn_description=fn_description,
-        )
-    msg = f"Unsupported pydantic version: {PYDANTIC_VERSION.major}"
-    raise NotImplementedError(msg)
+    return _create_subset_model_v2(
+        name,
+        model,
+        field_names,
+        descriptions=descriptions,
+        fn_description=fn_description,
+    )
 
 
-if IS_PYDANTIC_V2:
-    from pydantic import BaseModel as BaseModelV2
-    from pydantic.v1 import BaseModel as BaseModelV1
-
-    @overload
-    def get_fields(model: type[BaseModelV2]) -> dict[str, FieldInfoV2]: ...
-
-    @overload
-    def get_fields(model: BaseModelV2) -> dict[str, FieldInfoV2]: ...
-
-    @overload
-    def get_fields(model: type[BaseModelV1]) -> dict[str, FieldInfoV1]: ...
-
-    @overload
-    def get_fields(model: BaseModelV1) -> dict[str, FieldInfoV1]: ...
-
-    def get_fields(
-        model: Union[type[Union[BaseModelV2, BaseModelV1]], BaseModelV2, BaseModelV1],
-    ) -> Union[dict[str, FieldInfoV2], dict[str, FieldInfoV1]]:
-        """Get the field names of a Pydantic model."""
-        if hasattr(model, "model_fields"):
-            return model.model_fields
-
-        if hasattr(model, "__fields__"):
-            return model.__fields__  # type: ignore[return-value]
+def get_fields(
+    model: type[BaseModel],
+) -> dict[str, FieldInfo]:
+    """Get the field names of a Pydantic model."""
+    try:
+        return model.model_fields
+    except AttributeError as exc:
         msg = f"Expected a Pydantic model. Got {type(model)}"
-        raise TypeError(msg)
+        raise TypeError(msg) from exc
 
-elif IS_PYDANTIC_V1:
-    from pydantic import BaseModel as BaseModelV1_
-
-    def get_fields(  # type: ignore[no-redef]
-        model: Union[type[BaseModelV1_], BaseModelV1_],
-    ) -> dict[str, FieldInfoV1]:
-        """Get the field names of a Pydantic model."""
-        return model.__fields__  # type: ignore[return-value]
-
-else:
-    msg = f"Unsupported Pydantic version: {PYDANTIC_VERSION.major}"
-    raise ValueError(msg)
 
 _SchemaConfig = ConfigDict(
     arbitrary_types_allowed=True, frozen=True, protected_namespaces=()
@@ -458,17 +214,6 @@ def _create_root_model(
     if default_ is not NO_DEFAULT:
         base_class_attributes["root"] = default_
     with warnings.catch_warnings():
-        try:
-            if (
-                isinstance(type_, type)
-                and not isinstance(type_, GenericAlias)
-                and issubclass(type_, BaseModelV1)
-            ):
-                warnings.filterwarnings(
-                    action="ignore", category=PydanticDeprecationWarning
-                )
-        except TypeError:
-            pass
         custom_root_type = type(name, (RootModel,), base_class_attributes)
     return cast("type[BaseModel]", custom_root_type)
 
@@ -545,9 +290,6 @@ _RESERVED_NAMES = {key for key in dir(BaseModel) if not key.startswith("_")}
 
 def _remap_field_definitions(field_definitions: dict[str, Any]) -> dict[str, Any]:
     """This remaps fields to avoid colliding with internal pydantic fields."""
-    from pydantic import Field
-    from pydantic.fields import FieldInfo
-
     remapped = {}
     for key, value in field_definitions.items():
         if key.startswith("_") or key in _RESERVED_NAMES:
@@ -595,7 +337,7 @@ def create_model_v2(
         root: Type for a root model (RootModel)
 
     Returns:
-        Type[BaseModel]: The created model.
+        type[BaseModel]: The created model.
     """
     field_definitions = field_definitions or {}
 
diff --git a/libs/core/langchain_core/utils/utils.py b/libs/core/langchain_core/utils/utils.py
index a7467ec51e9..74392a2df3c 100644
--- a/libs/core/langchain_core/utils/utils.py
+++ b/libs/core/langchain_core/utils/utils.py
@@ -15,10 +15,6 @@ from pydantic import SecretStr
 from requests import HTTPError, Response
 from typing_extensions import override
 
-from langchain_core.utils.pydantic import (
-    is_pydantic_v1_subclass,
-)
-
 
 def xor_args(*arg_groups: tuple[str, ...]) -> Callable:
     """Validate specified keyword args are mutually exclusive.".
@@ -206,16 +202,10 @@ def get_pydantic_field_names(pydantic_cls: Any) -> set[str]:
         set[str]: Field names.
     """
     all_required_field_names = set()
-    if is_pydantic_v1_subclass(pydantic_cls):
-        for field in pydantic_cls.__fields__.values():
-            all_required_field_names.add(field.name)
-            if field.has_alias:
-                all_required_field_names.add(field.alias)
-    else:  # Assuming pydantic 2 for now
-        for name, field in pydantic_cls.model_fields.items():
-            all_required_field_names.add(name)
-            if field.alias:
-                all_required_field_names.add(field.alias)
+    for name, field in pydantic_cls.model_fields.items():
+        all_required_field_names.add(name)
+        if field.alias:
+            all_required_field_names.add(field.alias)
     return all_required_field_names
 
 
diff --git a/libs/core/pyproject.toml b/libs/core/pyproject.toml
index 785eb943f7d..0e0b742a823 100644
--- a/libs/core/pyproject.toml
+++ b/libs/core/pyproject.toml
@@ -125,7 +125,7 @@ filterwarnings = [ "ignore::langchain_core._api.beta_decorator.LangChainBetaWarn
 asyncio_default_fixture_loop_scope = "function"
 
 [tool.ruff.lint.pep8-naming]
-classmethod-decorators = [ "classmethod", "langchain_core.utils.pydantic.pre_init", "pydantic.field_validator", "pydantic.v1.root_validator",]
+classmethod-decorators = [ "classmethod", "langchain_core.utils.pydantic.pre_init", "pydantic.field_validator"]
 
 [tool.ruff.lint.per-file-ignores]
 "langchain_core/utils/mustache.py" = [ "PLW0603",]
diff --git a/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py b/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py
index 992e5c48c55..f5169f43b0d 100644
--- a/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py
+++ b/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py
@@ -16,10 +16,6 @@ from langchain_core.output_parsers.openai_tools import (
     PydanticToolsParser,
 )
 from langchain_core.outputs import ChatGeneration
-from langchain_core.utils.pydantic import (
-    IS_PYDANTIC_V1,
-    IS_PYDANTIC_V2,
-)
 
 STREAMED_MESSAGES: list = [
     AIMessageChunk(content=""),
@@ -532,87 +528,13 @@ async def test_partial_pydantic_output_parser_async() -> None:
         assert actual == EXPECTED_STREAMED_PYDANTIC
 
 
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="This test is for pydantic 2")
-def test_parse_with_different_pydantic_2_v1() -> None:
-    """Test with pydantic.v1.BaseModel from pydantic 2."""
-    import pydantic
+def test_parse_with_different_pydantic() -> None:
+    """Test with BaseModel"""
 
-    class Forecast(pydantic.v1.BaseModel):
+    class Forecast(BaseModel):
         temperature: int
         forecast: str
 
-    # Can't get pydantic to work here due to the odd typing of tryig to support
-    # both v1 and v2 in the same codebase.
-    parser = PydanticToolsParser(tools=[Forecast])  # type: ignore[list-item]
-    message = AIMessage(
-        content="",
-        tool_calls=[
-            {
-                "id": "call_OwL7f5PE",
-                "name": "Forecast",
-                "args": {"temperature": 20, "forecast": "Sunny"},
-            }
-        ],
-    )
-
-    generation = ChatGeneration(
-        message=message,
-    )
-
-    assert parser.parse_result([generation]) == [
-        Forecast(
-            temperature=20,
-            forecast="Sunny",
-        )
-    ]
-
-
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="This test is for pydantic 2")
-def test_parse_with_different_pydantic_2_proper() -> None:
-    """Test with pydantic.BaseModel from pydantic 2."""
-    import pydantic
-
-    class Forecast(pydantic.BaseModel):
-        temperature: int
-        forecast: str
-
-    # Can't get pydantic to work here due to the odd typing of tryig to support
-    # both v1 and v2 in the same codebase.
-    parser = PydanticToolsParser(tools=[Forecast])
-    message = AIMessage(
-        content="",
-        tool_calls=[
-            {
-                "id": "call_OwL7f5PE",
-                "name": "Forecast",
-                "args": {"temperature": 20, "forecast": "Sunny"},
-            }
-        ],
-    )
-
-    generation = ChatGeneration(
-        message=message,
-    )
-
-    assert parser.parse_result([generation]) == [
-        Forecast(
-            temperature=20,
-            forecast="Sunny",
-        )
-    ]
-
-
-@pytest.mark.skipif(not IS_PYDANTIC_V1, reason="This test is for pydantic 1")
-def test_parse_with_different_pydantic_1_proper() -> None:
-    """Test with pydantic.BaseModel from pydantic 1."""
-    import pydantic
-
-    class Forecast(pydantic.BaseModel):
-        temperature: int
-        forecast: str
-
-    # Can't get pydantic to work here due to the odd typing of tryig to support
-    # both v1 and v2 in the same codebase.
     parser = PydanticToolsParser(tools=[Forecast])
     message = AIMessage(
         content="",
diff --git a/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py b/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py
index 9c2d9da3f54..4713ef2b0d3 100644
--- a/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py
+++ b/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py
@@ -3,35 +3,23 @@
 from enum import Enum
 from typing import Literal, Optional
 
-import pydantic
 import pytest
 from pydantic import BaseModel, Field
-from pydantic.v1 import BaseModel as V1BaseModel
 
 from langchain_core.exceptions import OutputParserException
 from langchain_core.language_models import ParrotFakeChatModel
 from langchain_core.output_parsers import PydanticOutputParser
 from langchain_core.output_parsers.json import JsonOutputParser
 from langchain_core.prompts.prompt import PromptTemplate
-from langchain_core.utils.pydantic import TBaseModel
 
 
-class ForecastV2(pydantic.BaseModel):
+class Forecast(BaseModel):
     temperature: int
     f_or_c: Literal["F", "C"]
     forecast: str
 
 
-class ForecastV1(V1BaseModel):
-    temperature: int
-    f_or_c: Literal["F", "C"]
-    forecast: str
-
-
-@pytest.mark.parametrize("pydantic_object", [ForecastV2, ForecastV1])
-def test_pydantic_parser_chaining(
-    pydantic_object: TBaseModel,
-) -> None:
+def test_pydantic_parser_chaining() -> None:
     prompt = PromptTemplate(
         template="""{{
         "temperature": 20,
@@ -43,18 +31,17 @@ def test_pydantic_parser_chaining(
 
     model = ParrotFakeChatModel()
 
-    parser = PydanticOutputParser(pydantic_object=pydantic_object)  # type: ignore[arg-type,var-annotated]
+    parser = PydanticOutputParser(pydantic_object=Forecast)
     chain = prompt | model | parser
 
     res = chain.invoke({})
-    assert type(res) is pydantic_object
+    assert type(res) is Forecast
     assert res.f_or_c == "C"
     assert res.temperature == 20
     assert res.forecast == "Sunny"
 
 
-@pytest.mark.parametrize("pydantic_object", [ForecastV2, ForecastV1])
-def test_pydantic_parser_validation(pydantic_object: TBaseModel) -> None:
+def test_pydantic_parser_validation() -> None:
     bad_prompt = PromptTemplate(
         template="""{{
         "temperature": "oof",
@@ -66,17 +53,14 @@ def test_pydantic_parser_validation(pydantic_object: TBaseModel) -> None:
 
     model = ParrotFakeChatModel()
 
-    parser = PydanticOutputParser(pydantic_object=pydantic_object)  # type: ignore[arg-type,var-annotated]
+    parser = PydanticOutputParser(pydantic_object=Forecast)
     chain = bad_prompt | model | parser
     with pytest.raises(OutputParserException):
         chain.invoke({})
 
 
 # JSON output parser tests
-@pytest.mark.parametrize("pydantic_object", [ForecastV2, ForecastV1])
-def test_json_parser_chaining(
-    pydantic_object: TBaseModel,
-) -> None:
+def test_json_parser_chaining() -> None:
     prompt = PromptTemplate(
         template="""{{
         "temperature": 20,
@@ -88,7 +72,7 @@ def test_json_parser_chaining(
 
     model = ParrotFakeChatModel()
 
-    parser = JsonOutputParser(pydantic_object=pydantic_object)  # type: ignore[arg-type]
+    parser = JsonOutputParser(pydantic_object=Forecast)
     chain = prompt | model | parser
 
     res = chain.invoke({})
diff --git a/libs/core/tests/unit_tests/prompts/test_structured.py b/libs/core/tests/unit_tests/prompts/test_structured.py
index 8f04f2029ba..09d8a39d336 100644
--- a/libs/core/tests/unit_tests/prompts/test_structured.py
+++ b/libs/core/tests/unit_tests/prompts/test_structured.py
@@ -1,6 +1,5 @@
 from functools import partial
-from inspect import isclass
-from typing import Any, Union, cast
+from typing import Any, Union
 
 from pydantic import BaseModel
 
@@ -10,15 +9,14 @@ from langchain_core.load.load import loads
 from langchain_core.messages import HumanMessage
 from langchain_core.prompts.structured import StructuredPrompt
 from langchain_core.runnables.base import Runnable, RunnableLambda
-from langchain_core.utils.pydantic import is_basemodel_subclass
 
 
 def _fake_runnable(
     _: Any, *, schema: Union[dict, type[BaseModel]], value: Any = 42, **_kwargs: Any
 ) -> Union[BaseModel, dict]:
-    if isclass(schema) and is_basemodel_subclass(schema):
+    if isinstance(schema, type) and issubclass(schema, BaseModel):
         return schema(name="yo", value=value)
-    params = cast("dict", schema)["parameters"]
+    params = schema["parameters"]
     return {k: 1 if k != "value" else value for k, v in params.items()}
 
 
diff --git a/libs/core/tests/unit_tests/pydantic_utils.py b/libs/core/tests/unit_tests/pydantic_utils.py
index 8e7a9a078d7..8d9c604b69b 100644
--- a/libs/core/tests/unit_tests/pydantic_utils.py
+++ b/libs/core/tests/unit_tests/pydantic_utils.py
@@ -2,8 +2,6 @@ from typing import Any, Union
 
 from pydantic import BaseModel
 
-from langchain_core.utils.pydantic import is_basemodel_subclass
-
 
 # Function to replace allOf with $ref
 def replace_all_of_with_ref(schema: Any) -> None:
@@ -31,8 +29,6 @@ def replace_all_of_with_ref(schema: Any) -> None:
 def remove_all_none_default(schema: Any) -> None:
     """Removing all none defaults.
 
-    Pydantic v1 did not generate these, but Pydantic v2 does.
-
     The None defaults usually represent **NotRequired** fields, and the None value
     is actually **incorrect** as a value since the fields do not allow a None value.
 
@@ -75,13 +71,9 @@ def _remove_enum(obj: Any) -> None:
 
 def _schema(obj: Any) -> dict:
     """Return the schema of the object."""
-    if not is_basemodel_subclass(obj):
+    if not (isinstance(obj, type) and issubclass(obj, BaseModel)):
         msg = f"Object must be a Pydantic BaseModel subclass. Got {type(obj)}"
         raise TypeError(msg)
-    # Remap to old style schema
-    if not hasattr(obj, "model_json_schema"):  # V1 model
-        return obj.schema()
-
     schema_ = obj.model_json_schema(ref_template="#/definitions/{model}")
     if "$defs" in schema_:
         schema_["definitions"] = schema_["$defs"]
diff --git a/libs/core/tests/unit_tests/test_tools.py b/libs/core/tests/unit_tests/test_tools.py
index 025be61b461..eb879db2a3b 100644
--- a/libs/core/tests/unit_tests/test_tools.py
+++ b/libs/core/tests/unit_tests/test_tools.py
@@ -21,9 +21,7 @@ from typing import (
 )
 
 import pytest
-from pydantic import BaseModel, Field, ValidationError
-from pydantic.v1 import BaseModel as BaseModelV1
-from pydantic.v1 import ValidationError as ValidationErrorV1
+from pydantic import BaseModel, ConfigDict, Field, ValidationError
 from typing_extensions import TypedDict
 
 from langchain_core import tools
@@ -52,7 +50,6 @@ from langchain_core.tools import (
     tool,
 )
 from langchain_core.tools.base import (
-    ArgsSchema,
     InjectedToolArg,
     InjectedToolCallId,
     SchemaAnnotationError,
@@ -65,8 +62,6 @@ from langchain_core.utils.function_calling import (
     convert_to_openai_tool,
 )
 from langchain_core.utils.pydantic import (
-    IS_PYDANTIC_V1,
-    IS_PYDANTIC_V2,
     _create_subset_model,
     create_model_v2,
 )
@@ -79,9 +74,7 @@ def _get_tool_call_json_schema(tool: BaseTool) -> dict:
     if isinstance(tool_schema, dict):
         return tool_schema
 
-    if hasattr(tool_schema, "model_json_schema"):
-        return tool_schema.model_json_schema()
-    return tool_schema.schema()
+    return tool_schema.model_json_schema()
 
 
 def test_unnamed_decorator() -> None:
@@ -106,14 +99,6 @@ class _MockSchema(BaseModel):
     arg3: Optional[dict] = None
 
 
-class _MockSchemaV1(BaseModelV1):
-    """Return the arguments directly."""
-
-    arg1: int
-    arg2: bool
-    arg3: Optional[dict] = None
-
-
 class _MockStructuredTool(BaseTool):
     name: str = "structured_api"
     args_schema: type[BaseModel] = _MockSchema
@@ -205,13 +190,6 @@ def test_decorator_with_specified_schema() -> None:
     assert isinstance(tool_func, BaseTool)
     assert tool_func.args_schema == _MockSchema
 
-    @tool(args_schema=cast("ArgsSchema", _MockSchemaV1))
-    def tool_func_v1(*, arg1: int, arg2: bool, arg3: Optional[dict] = None) -> str:
-        return f"{arg1} {arg2} {arg3}"
-
-    assert isinstance(tool_func_v1, BaseTool)
-    assert tool_func_v1.args_schema == _MockSchemaV1
-
 
 def test_decorated_function_schema_equivalent() -> None:
     """Test that a BaseTool without a schema meets expectations."""
@@ -345,50 +323,6 @@ def test_structured_tool_types_parsed() -> None:
     assert result == expected
 
 
-def test_structured_tool_types_parsed_pydantic_v1() -> None:
-    """Test the non-primitive types are correctly passed to structured tools."""
-
-    class SomeBaseModel(BaseModelV1):
-        foo: str
-
-    class AnotherBaseModel(BaseModelV1):
-        bar: str
-
-    @tool
-    def structured_tool(some_base_model: SomeBaseModel) -> AnotherBaseModel:
-        """Return the arguments directly."""
-        return AnotherBaseModel(bar=some_base_model.foo)
-
-    assert isinstance(structured_tool, StructuredTool)
-
-    expected = AnotherBaseModel(bar="baz")
-    for arg in [
-        SomeBaseModel(foo="baz"),
-        SomeBaseModel(foo="baz").dict(),
-    ]:
-        args = {"some_base_model": arg}
-        result = structured_tool.run(args)
-        assert result == expected
-
-
-def test_structured_tool_types_parsed_pydantic_mixed() -> None:
-    """Test handling of tool with mixed Pydantic version arguments."""
-
-    class SomeBaseModel(BaseModelV1):
-        foo: str
-
-    class AnotherBaseModel(BaseModel):
-        bar: str
-
-    with pytest.raises(NotImplementedError):
-
-        @tool
-        def structured_tool(
-            some_base_model: SomeBaseModel, another_base_model: AnotherBaseModel
-        ) -> None:
-            """Return the arguments directly."""
-
-
 def test_base_tool_inheritance_base_schema() -> None:
     """Test schema is correctly inferred when inheriting from BaseTool."""
 
@@ -867,7 +801,7 @@ def test_validation_error_handling_callable() -> None:
     """Test that validation errors are handled correctly."""
     expected = "foo bar"
 
-    def handling(e: Union[ValidationError, ValidationErrorV1]) -> str:
+    def handling(e: ValidationError) -> str:
         return expected
 
     _tool = _MockStructuredTool(handle_validation_error=handling)
@@ -884,9 +818,7 @@ def test_validation_error_handling_callable() -> None:
     ],
 )
 def test_validation_error_handling_non_validation_error(
-    handler: Union[
-        bool, str, Callable[[Union[ValidationError, ValidationErrorV1]], str]
-    ],
+    handler: Union[bool, str, Callable[[ValidationError], str]],
 ) -> None:
     """Test that validation errors are handled correctly."""
 
@@ -932,7 +864,7 @@ async def test_async_validation_error_handling_callable() -> None:
     """Test that validation errors are handled correctly."""
     expected = "foo bar"
 
-    def handling(e: Union[ValidationError, ValidationErrorV1]) -> str:
+    def handling(e: ValidationError) -> str:
         return expected
 
     _tool = _MockStructuredTool(handle_validation_error=handling)
@@ -949,9 +881,7 @@ async def test_async_validation_error_handling_callable() -> None:
     ],
 )
 async def test_async_validation_error_handling_non_validation_error(
-    handler: Union[
-        bool, str, Callable[[Union[ValidationError, ValidationErrorV1]], str]
-    ],
+    handler: Union[bool, str, Callable[[ValidationError], str]],
 ) -> None:
     """Test that validation errors are handled correctly."""
 
@@ -1812,38 +1742,18 @@ def test_fn_injected_arg_with_schema(tool_: Callable) -> None:
     }
 
 
-def generate_models() -> list[Any]:
-    """Generate a list of base models depending on the pydantic version."""
-
-    class FooProper(BaseModel):
-        a: int
-        b: str
-
-    return [FooProper]
+class FooProper(BaseModel):
+    a: int
+    b: str
 
 
-def generate_backwards_compatible_v1() -> list[Any]:
-    """Generate a model with pydantic 2 from the v1 namespace."""
-    from pydantic.v1 import BaseModel as BaseModelV1
-
-    class FooV1Namespace(BaseModelV1):
-        a: int
-        b: str
-
-    return [FooV1Namespace]
-
-
-# This generates a list of models that can be used for testing that our APIs
-# behave well with either pydantic 1 proper,
-# pydantic v1 from pydantic 2,
-# or pydantic 2 proper.
-TEST_MODELS = generate_models() + generate_backwards_compatible_v1()
+TEST_MODELS = [FooProper]
 
 
 @pytest.mark.parametrize("pydantic_model", TEST_MODELS)
 def test_args_schema_as_pydantic(pydantic_model: Any) -> None:
     class SomeTool(BaseTool):
-        args_schema: type[pydantic_model] = pydantic_model
+        args_schema: type[BaseModel] = pydantic_model
 
         def _run(self, *args: Any, **kwargs: Any) -> str:
             return "foo"
@@ -1853,11 +1763,7 @@ def test_args_schema_as_pydantic(pydantic_model: Any) -> None:
     )
 
     input_schema = tool.get_input_schema()
-    input_json_schema = (
-        input_schema.model_json_schema()
-        if hasattr(input_schema, "model_json_schema")
-        else input_schema.schema()
-    )
+    input_json_schema = input_schema.model_json_schema()
     assert input_json_schema == {
         "properties": {
             "a": {"title": "A", "type": "integer"},
@@ -1882,22 +1788,13 @@ def test_args_schema_as_pydantic(pydantic_model: Any) -> None:
 
 
 def test_args_schema_explicitly_typed() -> None:
-    """This should test that one can type the args schema as a pydantic model.
-
-    Please note that this will test using pydantic 2 even though BaseTool
-    is a pydantic 1 model!
-    """
-    # Check with whatever pydantic model is passed in and not via v1 namespace
-    from pydantic import BaseModel
+    """This should test that one can type the args schema as a pydantic model."""
 
     class Foo(BaseModel):
         a: int
         b: str
 
     class SomeTool(BaseTool):
-        # type ignoring here since we're allowing overriding a type
-        # signature of pydantic.v1.BaseModel with pydantic.BaseModel
-        # for pydantic 2!
         args_schema: type[BaseModel] = Foo
 
         def _run(self, *args: Any, **kwargs: Any) -> str:
@@ -1944,11 +1841,7 @@ def test_structured_tool_with_different_pydantic_versions(pydantic_model: Any) -
     assert foo_tool.invoke({"a": 5, "b": "hello"}) == "foo"
 
     args_schema = cast("BaseModel", foo_tool.args_schema)
-    args_json_schema = (
-        args_schema.model_json_schema()
-        if hasattr(args_schema, "model_json_schema")
-        else args_schema.schema()
-    )
+    args_json_schema = args_schema.model_json_schema()
     assert args_json_schema == {
         "properties": {
             "a": {"title": "A", "type": "integer"},
@@ -1960,11 +1853,7 @@ def test_structured_tool_with_different_pydantic_versions(pydantic_model: Any) -
     }
 
     input_schema = foo_tool.get_input_schema()
-    input_json_schema = (
-        input_schema.model_json_schema()
-        if hasattr(input_schema, "model_json_schema")
-        else input_schema.schema()
-    )
+    input_json_schema = input_schema.model_json_schema()
     assert input_json_schema == {
         "properties": {
             "a": {"title": "A", "type": "integer"},
@@ -2020,81 +1909,12 @@ def test__is_message_content_type(obj: Any, *, expected: bool) -> None:
     assert _is_message_content_type(obj) is expected
 
 
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="Testing pydantic v2.")
-@pytest.mark.parametrize("use_v1_namespace", [True, False])
-def test__get_all_basemodel_annotations_v2(*, use_v1_namespace: bool) -> None:
+def test__get_all_basemodel_annotations_v2() -> None:
     A = TypeVar("A")
 
-    if use_v1_namespace:
-        from pydantic.v1 import BaseModel as BaseModel1
-
-        class ModelA(BaseModel1, Generic[A], extra="allow"):
-            a: A
-
-    else:
-        from pydantic import BaseModel as BaseModel2
-        from pydantic import ConfigDict
-
-        class ModelA(BaseModel2, Generic[A]):  # type: ignore[no-redef]
-            a: A
-            model_config = ConfigDict(arbitrary_types_allowed=True, extra="allow")
-
-    class ModelB(ModelA[str]):
-        b: Annotated[ModelA[dict[str, Any]], "foo"]
-
-    class Mixin:
-        def foo(self) -> str:
-            return "foo"
-
-    class ModelC(Mixin, ModelB):
-        c: dict
-
-    expected = {"a": str, "b": Annotated[ModelA[dict[str, Any]], "foo"], "c": dict}
-    actual = get_all_basemodel_annotations(ModelC)
-    assert actual == expected
-
-    expected = {"a": str, "b": Annotated[ModelA[dict[str, Any]], "foo"]}
-    actual = get_all_basemodel_annotations(ModelB)
-    assert actual == expected
-
-    expected = {"a": Any}
-    actual = get_all_basemodel_annotations(ModelA)
-    assert actual == expected
-
-    expected = {"a": int}
-    actual = get_all_basemodel_annotations(ModelA[int])
-    assert actual == expected
-
-    D = TypeVar("D", bound=Union[str, int])
-
-    class ModelD(ModelC, Generic[D]):
-        d: Optional[D]
-
-    expected = {
-        "a": str,
-        "b": Annotated[ModelA[dict[str, Any]], "foo"],
-        "c": dict,
-        "d": Union[str, int, None],
-    }
-    actual = get_all_basemodel_annotations(ModelD)
-    assert actual == expected
-
-    expected = {
-        "a": str,
-        "b": Annotated[ModelA[dict[str, Any]], "foo"],
-        "c": dict,
-        "d": Union[int, None],
-    }
-    actual = get_all_basemodel_annotations(ModelD[int])
-    assert actual == expected
-
-
-@pytest.mark.skipif(not IS_PYDANTIC_V1, reason="Testing pydantic v1.")
-def test__get_all_basemodel_annotations_v1() -> None:
-    A = TypeVar("A")
-
-    class ModelA(BaseModel, Generic[A], extra="allow"):
+    class ModelA(BaseModel, Generic[A]):
         a: A
+        model_config = ConfigDict(arbitrary_types_allowed=True, extra="allow")
 
     class ModelB(ModelA[str]):
         b: Annotated[ModelA[dict[str, Any]], "foo"]
@@ -2226,14 +2046,9 @@ def test_create_retriever_tool() -> None:
     )
 
 
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="Testing pydantic v2.")
-def test_tool_args_schema_pydantic_v2_with_metadata() -> None:
-    from pydantic import BaseModel as BaseModelV2
-    from pydantic import Field as FieldV2
-    from pydantic import ValidationError as ValidationErrorV2
-
-    class Foo(BaseModelV2):
-        x: list[int] = FieldV2(
+def test_tool_args_schema_pydantic_with_metadata() -> None:
+    class Foo(BaseModel):
+        x: list[int] = Field(
             description="List of integers", min_length=10, max_length=15
         )
 
@@ -2260,7 +2075,7 @@ def test_tool_args_schema_pydantic_v2_with_metadata() -> None:
     }
 
     assert foo.invoke({"x": [0] * 10})
-    with pytest.raises(ValidationErrorV2):
+    with pytest.raises(ValidationError):
         foo.invoke({"x": [0] * 9})
 
 
diff --git a/libs/core/tests/unit_tests/utils/test_function_calling.py b/libs/core/tests/unit_tests/utils/test_function_calling.py
index 126c1753f4e..adc2f105c11 100644
--- a/libs/core/tests/unit_tests/utils/test_function_calling.py
+++ b/libs/core/tests/unit_tests/utils/test_function_calling.py
@@ -746,7 +746,7 @@ def test_tool_outputs() -> None:
     [ExtensionsAnnotated, TypingAnnotated],
     ids=["typing_extensions.Annotated", "typing.Annotated"],
 )
-def test__convert_typed_dict_to_openai_function(
+def test_convert_typed_dict_to_openai_function(
     typed_dict: TypeAlias, annotated: TypeAlias
 ) -> None:
     class SubTool(typed_dict):  # type: ignore[misc]
@@ -985,7 +985,7 @@ def test__convert_typed_dict_to_openai_function(
 @pytest.mark.parametrize("typed_dict", [ExtensionsTypedDict, TypingTypedDict])
 def test__convert_typed_dict_to_openai_function_fail(typed_dict: type) -> None:
     class Tool(typed_dict):  # type: ignore[misc]
-        arg1: typing.MutableSet  # Pydantic 2 supports this, but pydantic v1 does not.
+        arg1: typing.MutableSet
 
     # Error should be raised since we're using v1 code path here
     with pytest.raises(TypeError):
diff --git a/libs/core/tests/unit_tests/utils/test_pydantic.py b/libs/core/tests/unit_tests/utils/test_pydantic.py
index 88ca45ff1d8..21516991c56 100644
--- a/libs/core/tests/unit_tests/utils/test_pydantic.py
+++ b/libs/core/tests/unit_tests/utils/test_pydantic.py
@@ -3,18 +3,12 @@
 import warnings
 from typing import Any, Optional
 
-import pytest
-from pydantic import ConfigDict
+from pydantic import BaseModel, ConfigDict
 
 from langchain_core.utils.pydantic import (
-    IS_PYDANTIC_V1,
-    IS_PYDANTIC_V2,
-    PYDANTIC_VERSION,
     _create_subset_model_v2,
     create_model_v2,
     get_fields,
-    is_basemodel_instance,
-    is_basemodel_subclass,
     pre_init,
 )
 
@@ -94,52 +88,6 @@ def test_with_aliases() -> None:
     assert foo.z == 2
 
 
-def test_is_basemodel_subclass() -> None:
-    """Test pydantic."""
-    if IS_PYDANTIC_V1:
-        from pydantic import BaseModel as BaseModelV1Proper
-
-        assert is_basemodel_subclass(BaseModelV1Proper)
-    elif IS_PYDANTIC_V2:
-        from pydantic import BaseModel as BaseModelV2
-        from pydantic.v1 import BaseModel as BaseModelV1
-
-        assert is_basemodel_subclass(BaseModelV2)
-
-        assert is_basemodel_subclass(BaseModelV1)
-    else:
-        msg = f"Unsupported Pydantic version: {PYDANTIC_VERSION.major}"
-        raise ValueError(msg)
-
-
-def test_is_basemodel_instance() -> None:
-    """Test pydantic."""
-    if IS_PYDANTIC_V1:
-        from pydantic import BaseModel as BaseModelV1Proper
-
-        class FooV1(BaseModelV1Proper):
-            x: int
-
-        assert is_basemodel_instance(FooV1(x=5))
-    elif IS_PYDANTIC_V2:
-        from pydantic import BaseModel as BaseModelV2
-        from pydantic.v1 import BaseModel as BaseModelV1
-
-        class Foo(BaseModelV2):
-            x: int
-
-        assert is_basemodel_instance(Foo(x=5))
-
-        class Bar(BaseModelV1):
-            x: int
-
-        assert is_basemodel_instance(Bar(x=5))
-    else:
-        msg = f"Unsupported Pydantic version: {PYDANTIC_VERSION.major}"
-        raise ValueError(msg)
-
-
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="Only tests Pydantic v2")
 def test_with_field_metadata() -> None:
     """Test pydantic with field metadata."""
     from pydantic import BaseModel as BaseModelV2
@@ -168,21 +116,7 @@ def test_with_field_metadata() -> None:
     }
 
 
-@pytest.mark.skipif(not IS_PYDANTIC_V1, reason="Only tests Pydantic v1")
-def test_fields_pydantic_v1() -> None:
-    from pydantic import BaseModel
-
-    class Foo(BaseModel):
-        x: int
-
-    fields = get_fields(Foo)
-    assert fields == {"x": Foo.model_fields["x"]}
-
-
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="Only tests Pydantic v2")
 def test_fields_pydantic_v2_proper() -> None:
-    from pydantic import BaseModel
-
     class Foo(BaseModel):
         x: int
 
@@ -190,17 +124,6 @@ def test_fields_pydantic_v2_proper() -> None:
     assert fields == {"x": Foo.model_fields["x"]}
 
 
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="Only tests Pydantic v2")
-def test_fields_pydantic_v1_from_2() -> None:
-    from pydantic.v1 import BaseModel
-
-    class Foo(BaseModel):
-        x: int
-
-    fields = get_fields(Foo)
-    assert fields == {"x": Foo.__fields__["x"]}
-
-
 def test_create_model_v2() -> None:
     """Test that create model v2 works as expected."""
     with warnings.catch_warnings(record=True) as record:
diff --git a/libs/core/tests/unit_tests/utils/test_utils.py b/libs/core/tests/unit_tests/utils/test_utils.py
index 258b447409b..87847ab6985 100644
--- a/libs/core/tests/unit_tests/utils/test_utils.py
+++ b/libs/core/tests/unit_tests/utils/test_utils.py
@@ -6,7 +6,7 @@ from typing import Any, Callable, Optional, Union
 from unittest.mock import patch
 
 import pytest
-from pydantic import SecretStr
+from pydantic import BaseModel, Field, SecretStr
 
 from langchain_core import utils
 from langchain_core.utils import (
@@ -16,10 +16,6 @@ from langchain_core.utils import (
     guard_import,
 )
 from langchain_core.utils._merge import merge_dicts
-from langchain_core.utils.pydantic import (
-    IS_PYDANTIC_V1,
-    IS_PYDANTIC_V2,
-)
 from langchain_core.utils.utils import secret_from_env
 
 
@@ -214,39 +210,7 @@ def test_guard_import_failure(
         guard_import(module_name, pip_name=pip_name, package=package)
 
 
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="Requires pydantic 2")
-def test_get_pydantic_field_names_v1_in_2() -> None:
-    from pydantic.v1 import BaseModel as PydanticV1BaseModel
-    from pydantic.v1 import Field
-
-    class PydanticV1Model(PydanticV1BaseModel):
-        field1: str
-        field2: int
-        alias_field: int = Field(alias="aliased_field")
-
-    result = get_pydantic_field_names(PydanticV1Model)
-    expected = {"field1", "field2", "aliased_field", "alias_field"}
-    assert result == expected
-
-
-@pytest.mark.skipif(not IS_PYDANTIC_V2, reason="Requires pydantic 2")
-def test_get_pydantic_field_names_v2_in_2() -> None:
-    from pydantic import BaseModel, Field
-
-    class PydanticModel(BaseModel):
-        field1: str
-        field2: int
-        alias_field: int = Field(alias="aliased_field")
-
-    result = get_pydantic_field_names(PydanticModel)
-    expected = {"field1", "field2", "aliased_field", "alias_field"}
-    assert result == expected
-
-
-@pytest.mark.skipif(not IS_PYDANTIC_V1, reason="Requires pydantic 1")
-def test_get_pydantic_field_names_v1() -> None:
-    from pydantic import BaseModel, Field
-
+def test_get_pydantic_field_names() -> None:
     class PydanticModel(BaseModel):
         field1: str
         field2: int