diff --git a/api_core/google/api_core/bidi.py b/api_core/google/api_core/bidi.py
index 68d13001a772..be24d32c17c1 100644
--- a/api_core/google/api_core/bidi.py
+++ b/api_core/google/api_core/bidi.py
@@ -350,7 +350,7 @@ def _reopen(self):
             self.call = None
             # Request generator should exit cleanly since the RPC its bound to
             # has exited.
-            self.request_generator = None
+            self._request_generator = None
 
             # Note: we do not currently do any sort of backoff here. The
             # assumption is that re-establishing the stream under normal