diff --git a/litellm/llms/chatgpt/responses/transformation.py b/litellm/llms/chatgpt/responses/transformation.py
index 66acd933416..6aae2c48b58 100644
--- a/litellm/llms/chatgpt/responses/transformation.py
+++ b/litellm/llms/chatgpt/responses/transformation.py
@@ -134,6 +134,7 @@ class ChatGPTResponsesAPIConfig(OpenAIResponsesAPIConfig):
 
         completed_response = None
         error_message = None
+        collected_output_items: list = []
         for chunk in body_text.splitlines():
             stripped_chunk = CustomStreamWrapper._strip_sse_data_from_chunk(chunk)
             if not stripped_chunk:
@@ -150,10 +151,21 @@ class ChatGPTResponsesAPIConfig(OpenAIResponsesAPIConfig):
             if not isinstance(parsed_chunk, dict):
                 continue
             event_type = parsed_chunk.get("type")
+            if event_type == ResponsesAPIStreamEvents.OUTPUT_ITEM_DONE:
+                item = parsed_chunk.get("item")
+                if isinstance(item, dict):
+                    collected_output_items.append(item)
+                continue
             if event_type == ResponsesAPIStreamEvents.RESPONSE_COMPLETED:
                 response_payload = parsed_chunk.get("response")
                 if isinstance(response_payload, dict):
                     response_payload = dict(response_payload)
+                    # ChatGPT backend leaves response.output empty on the final
+                    # `response.completed` event and emits items via earlier
+                    # `response.output_item.done` events; reassemble here so
+                    # non-streaming clients receive a populated output array.
+                    if not response_payload.get("output") and collected_output_items:
+                        response_payload["output"] = collected_output_items
                     if "created_at" in response_payload:
                         response_payload["created_at"] = _safe_convert_created_field(
                             response_payload["created_at"]