diff --git a/libs/partners/groq/langchain_groq/chat_models.py b/libs/partners/groq/langchain_groq/chat_models.py
index f8e518cc4fe21..5868e9cc6a3a4 100644
--- a/libs/partners/groq/langchain_groq/chat_models.py
+++ b/libs/partners/groq/langchain_groq/chat_models.py
@@ -305,7 +305,7 @@ class Joke(BaseModel):
     """Model name to use."""
     temperature: float = 0.7
     """What sampling temperature to use."""
-    stop: Optional[Union[List[str], str]] = Field(None, alias="stop_sequences")
+    stop: Optional[Union[List[str], str]] = Field(default=None, alias="stop_sequences")
     """Default stop sequences."""
     model_kwargs: Dict[str, Any] = Field(default_factory=dict)
     """Holds any model parameters valid for `create` call not explicitly specified."""