diff --git a/src/httpcore2/httpcore2/_async/http2.py b/src/httpcore2/httpcore2/_async/http2.py
index ae3e764c..7cea171f 100644
--- a/src/httpcore2/httpcore2/_async/http2.py
+++ b/src/httpcore2/httpcore2/_async/http2.py
@@ -377,8 +377,8 @@ async def _receive_remote_settings_change(self, event: h2.events.RemoteSettingsC
 
     async def _response_closed(self, stream_id: int) -> None:
         await self._max_streams_semaphore.release()
-        del self._events[stream_id]
         async with self._state_lock:
+            del self._events[stream_id]
             if self._connection_terminated and not self._events:
                 await self.aclose()
 
diff --git a/src/httpcore2/httpcore2/_sync/http2.py b/src/httpcore2/httpcore2/_sync/http2.py
index 0512c4a2..12d37de4 100644
--- a/src/httpcore2/httpcore2/_sync/http2.py
+++ b/src/httpcore2/httpcore2/_sync/http2.py
@@ -377,8 +377,8 @@ def _receive_remote_settings_change(self, event: h2.events.RemoteSettingsChanged
 
     def _response_closed(self, stream_id: int) -> None:
         self._max_streams_semaphore.release()
-        del self._events[stream_id]
         with self._state_lock:
+            del self._events[stream_id]
             if self._connection_terminated and not self._events:
                 self.close()