diff --git a/src/openai/lib/_parsing/_responses.py b/src/openai/lib/_parsing/_responses.py
index 232718cef6..ad2297e249 100644
--- a/src/openai/lib/_parsing/_responses.py
+++ b/src/openai/lib/_parsing/_responses.py
@@ -58,7 +58,7 @@ def parse_response(
 ) -> ParsedResponse[TextFormatT]:
     output_list: List[ParsedResponseOutputItem[TextFormatT]] = []
 
-    for output in response.output:
+    for output in (response.output or []):
         if output.type == "message":
             content_list: List[ParsedContent[TextFormatT]] = []
             for item in output.content:
diff --git a/src/openai/lib/streaming/responses/_responses.py b/src/openai/lib/streaming/responses/_responses.py
index 6975a9260d..8fd9e5f480 100644
--- a/src/openai/lib/streaming/responses/_responses.py
+++ b/src/openai/lib/streaming/responses/_responses.py
@@ -357,9 +357,15 @@ def accumulate_event(self, event: RawResponseStreamEvent) -> ParsedResponseSnaps
             if output.type == "function_call":
                 output.arguments += event.delta
         elif event.type == "response.completed":
+            completed_response = event.response
+            if completed_response.output is None and snapshot.output:
+                completed_response = construct_type_unchecked(
+                    type_=type(event.response),
+                    value={**event.response.to_dict(), "output": [item.to_dict() for item in snapshot.output]},
+                )
             self._completed_response = parse_response(
                 text_format=self._text_format,
-                response=event.response,
+                response=completed_response,
                 input_tools=self._input_tools,
             )