diff --git a/src/openai/lib/azure.py b/src/openai/lib/azure.py
index 165b9b82e2..cbe57b7b98 100644
--- a/src/openai/lib/azure.py
+++ b/src/openai/lib/azure.py
@@ -519,7 +519,7 @@ async def _get_azure_ad_token(self) -> str | None:
                 raise ValueError(
                     f"Expected `azure_ad_token_provider` argument to return a string but it returned {token}",
                 )
-            return token
+            return str(token)
 
         return None