diff --git a/src/callback_queue-inl.h b/src/callback_queue-inl.h
index e83c81cd0dd802..8c6919912e161b 100644
--- a/src/callback_queue-inl.h
+++ b/src/callback_queue-inl.h
@@ -22,8 +22,8 @@ CallbackQueue<R, Args...>::Shift() {
     head_ = ret->get_next();
     if (!head_)
       tail_ = nullptr;  // The queue is now empty.
+    size_--;
   }
-  size_--;
   return ret;
 }