diff --git a/.changeset/cuddly-boxes-look.md b/.changeset/cuddly-boxes-look.md
new file mode 100644
index 000000000..50947aa55
--- /dev/null
+++ b/.changeset/cuddly-boxes-look.md
@@ -0,0 +1,5 @@
+---
+"livekit-plugins-openai": patch
+---
+
+fix: Azure realtime model does not accept null for max_response_output_tokens
diff --git a/livekit-plugins/livekit-plugins-openai/livekit/plugins/openai/realtime/realtime_model.py b/livekit-plugins/livekit-plugins-openai/livekit/plugins/openai/realtime/realtime_model.py
index aa02e51fc..87d518b1d 100644
--- a/livekit-plugins/livekit-plugins-openai/livekit/plugins/openai/realtime/realtime_model.py
+++ b/livekit-plugins/livekit-plugins-openai/livekit/plugins/openai/realtime/realtime_model.py
@@ -757,6 +757,8 @@ def session_update(
             session_data["max_response_output_tokens"] = (
                 self._opts.max_response_output_tokens
             )
+        else:
+            del session_data["max_response_output_tokens"]  # type: ignore
 
         self._queue_msg(
             {