diff --git a/src/openai/resources/chat/completions.py b/src/openai/resources/chat/completions.py
index ceaf3c2fec..2bb2671fbb 100644
--- a/src/openai/resources/chat/completions.py
+++ b/src/openai/resources/chat/completions.py
@@ -812,6 +812,7 @@ def create(
         timeout: float | httpx.Timeout | None | NotGiven = NOT_GIVEN,
     ) -> ChatCompletion | Stream[ChatCompletionChunk]:
         validate_response_format(response_format)
+        extra_headers = {"Accept": "text/event-stream", **(extra_headers or {})} if stream else extra_headers
         return self._post(
             "/chat/completions",
             body=maybe_transform(