diff --git a/python/semantic_kernel/agents/open_ai/open_ai_assistant_base.py b/python/semantic_kernel/agents/open_ai/open_ai_assistant_base.py
index 367eb8c9d976..7885bf857168 100644
--- a/python/semantic_kernel/agents/open_ai/open_ai_assistant_base.py
+++ b/python/semantic_kernel/agents/open_ai/open_ai_assistant_base.py
@@ -1227,7 +1227,7 @@ def _generate_options(
             "model": merged_options.get("ai_model_id"),
             "top_p": merged_options.get("top_p"),
             # TODO(evmattso): Support `parallel_tool_calls` when it is ready
-            "response_format": "json" if merged_options.get("enable_json_response") else None,
+            "response_format": {"type": "json_object"} if merged_options.get("enable_json_response") else None,
             "temperature": merged_options.get("temperature"),
             "truncation_strategy": truncation_message_count if truncation_message_count else None,
             "metadata": merged_options.get("metadata", None),
diff --git a/python/tests/unit/agents/test_open_ai_assistant_base.py b/python/tests/unit/agents/test_open_ai_assistant_base.py
index 66e2f0b29f6b..660f72226b74 100644
--- a/python/tests/unit/agents/test_open_ai_assistant_base.py
+++ b/python/tests/unit/agents/test_open_ai_assistant_base.py
@@ -1439,7 +1439,7 @@ async def test_invoke_stream_with_instructions(
             temperature=0.7,
             top_p=0.9,
             model="test_model",
-            response_format="json",
+            response_format={"type": "json_object"},
             metadata={},
         )
 
@@ -1461,7 +1461,7 @@ async def test_invoke_stream_with_instructions(
             temperature=0.7,
             top_p=0.9,
             model="test_model",
-            response_format="json",
+            response_format={"type": "json_object"},
             metadata={},
         )
 
@@ -1512,7 +1512,7 @@ async def test_invoke_stream_with_instructions_override(
             temperature=0.7,
             top_p=0.9,
             model="test_model",
-            response_format="json",
+            response_format={"type": "json_object"},
             metadata={},
         )