diff --git a/libs/partners/openrouter/langchain_openrouter/chat_models.py b/libs/partners/openrouter/langchain_openrouter/chat_models.py
index 0e591c6a0cb..c9526a3ca4e 100644
--- a/libs/partners/openrouter/langchain_openrouter/chat_models.py
+++ b/libs/partners/openrouter/langchain_openrouter/chat_models.py
@@ -837,6 +837,7 @@ class ChatOpenRouter(BaseChatModel):
         *,
         tool_choice: dict | str | bool | None = None,
         strict: bool | None = None,
+        parallel_tool_calls: bool | None = None,
         **kwargs: Any,
     ) -> Runnable[LanguageModelInput, AIMessage]:
         """Bind tool-like objects to this chat model.
@@ -852,8 +853,13 @@ class ChatOpenRouter(BaseChatModel):
 
                 If `None`, the `strict` argument will not be passed to
                 the model.
+            parallel_tool_calls: Set to `False` to disable parallel tool use.
+                Defaults to `None` (no specification, which allows parallel
+                tool use).
             **kwargs: Any additional parameters.
         """
+        if parallel_tool_calls is not None:
+            kwargs["parallel_tool_calls"] = parallel_tool_calls
         formatted_tools = [
             convert_to_openai_tool(tool, strict=strict) for tool in tools
         ]
diff --git a/libs/partners/openrouter/tests/unit_tests/test_chat_models.py b/libs/partners/openrouter/tests/unit_tests/test_chat_models.py
index 4ba52979164..4d62e042374 100644
--- a/libs/partners/openrouter/tests/unit_tests/test_chat_models.py
+++ b/libs/partners/openrouter/tests/unit_tests/test_chat_models.py
@@ -1044,6 +1044,20 @@ class TestBindTools:
         tools = bound.kwargs["tools"]
         assert "strict" not in tools[0]["function"]
 
+    def test_bind_tools_parallel_tool_calls_forwarded(self) -> None:
+        """Test that parallel_tool_calls is forwarded to the request kwargs."""
+        model = _make_model()
+        bound = model.bind_tools([GetWeather], parallel_tool_calls=False)
+        assert isinstance(bound, RunnableBinding)
+        assert bound.kwargs["parallel_tool_calls"] is False
+
+    def test_bind_tools_parallel_tool_calls_none_omits_key(self) -> None:
+        """Test that parallel_tool_calls=None does not set the key in kwargs."""
+        model = _make_model()
+        bound = model.bind_tools([GetWeather])
+        assert isinstance(bound, RunnableBinding)
+        assert "parallel_tool_calls" not in bound.kwargs
+
 
 # ===========================================================================
 # with_structured_output tests