diff --git a/libs/partners/anthropic/langchain_anthropic/chat_models.py b/libs/partners/anthropic/langchain_anthropic/chat_models.py
index 73b60dfa2ab..cdb3a6c5a5e 100644
--- a/libs/partners/anthropic/langchain_anthropic/chat_models.py
+++ b/libs/partners/anthropic/langchain_anthropic/chat_models.py
@@ -259,7 +259,7 @@ class ChatAnthropic(BaseChatModel):
     _client: anthropic.Client = Field(default=None)
     _async_client: anthropic.AsyncClient = Field(default=None)
 
-    model: str = Field(alias="model_name")
+    model: str = Field(default="claude-3-haiku-20240307", alias="model_name")
     """Model name to use."""
 
     max_tokens: int = Field(default=1024, alias="max_tokens_to_sample")