diff --git a/libs/partners/openai/langchain_openai/chat_models/azure.py b/libs/partners/openai/langchain_openai/chat_models/azure.py
index f034da0da2b..240d6c876f3 100644
--- a/libs/partners/openai/langchain_openai/chat_models/azure.py
+++ b/libs/partners/openai/langchain_openai/chat_models/azure.py
@@ -677,8 +677,8 @@ class AzureChatOpenAI(BaseChatOpenAI):
             "base_url": self.openai_api_base,
             "timeout": self.request_timeout,
             "default_headers": {
-                **(self.default_headers or {}),
                 "User-Agent": "langchain-partner-python-azure-openai",
+                **(self.default_headers or {}),
             },
             "default_query": self.default_query,
         }
diff --git a/libs/partners/openai/langchain_openai/embeddings/azure.py b/libs/partners/openai/langchain_openai/embeddings/azure.py
index 1c854dbf292..a84b58ee6ff 100644
--- a/libs/partners/openai/langchain_openai/embeddings/azure.py
+++ b/libs/partners/openai/langchain_openai/embeddings/azure.py
@@ -200,8 +200,8 @@ class AzureOpenAIEmbeddings(OpenAIEmbeddings):  # type: ignore[override]
             "timeout": self.request_timeout,
             "max_retries": self.max_retries,
             "default_headers": {
-                **(self.default_headers or {}),
                 "User-Agent": "langchain-partner-python-azure-openai",
+                **(self.default_headers or {}),
             },
             "default_query": self.default_query,
         }
diff --git a/libs/partners/openai/langchain_openai/llms/azure.py b/libs/partners/openai/langchain_openai/llms/azure.py
index e86e9113867..723bd7e346c 100644
--- a/libs/partners/openai/langchain_openai/llms/azure.py
+++ b/libs/partners/openai/langchain_openai/llms/azure.py
@@ -169,8 +169,8 @@ class AzureOpenAI(BaseOpenAI):
             "timeout": self.request_timeout,
             "max_retries": self.max_retries,
             "default_headers": {
-                **(self.default_headers or {}),
                 "User-Agent": "langchain-partner-python-azure-openai",
+                **(self.default_headers or {}),
             },
             "default_query": self.default_query,
         }