diff --git a/src/agents/models/openai_chatcompletions.py b/src/agents/models/openai_chatcompletions.py
index c12fe68a..712a7998 100644
--- a/src/agents/models/openai_chatcompletions.py
+++ b/src/agents/models/openai_chatcompletions.py
@@ -500,7 +500,11 @@ async def _fetch_response(
             span.span_data.input = converted_messages
 
         parallel_tool_calls = (
-            True if model_settings.parallel_tool_calls and tools and len(tools) > 0 else NOT_GIVEN
+            True
+            if model_settings.parallel_tool_calls and tools and len(tools) > 0
+            else False
+            if model_settings.parallel_tool_calls is False
+            else NOT_GIVEN
         )
         tool_choice = _Converter.convert_tool_choice(model_settings.tool_choice)
         response_format = _Converter.convert_response_format(output_schema)