diff --git a/src/agents/models/openai_responses.py b/src/agents/models/openai_responses.py
index 3eea39ce..b9547123 100644
--- a/src/agents/models/openai_responses.py
+++ b/src/agents/models/openai_responses.py
@@ -208,7 +208,9 @@ async def _fetch_response(
         list_input = ItemHelpers.input_to_new_input_list(input)
 
         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)