diff --git a/google/cloud/firestore_v1/stream_generator.py b/google/cloud/firestore_v1/stream_generator.py
index 7e39a3fba..b4b585601 100644
--- a/google/cloud/firestore_v1/stream_generator.py
+++ b/google/cloud/firestore_v1/stream_generator.py
@@ -50,7 +50,7 @@ def __init__(
         self._explain_options = explain_options
         self._explain_metrics = None
 
-    def __iter__(self) -> StreamGenerator:
+    def __iter__(self) -> StreamGenerator[T]:
         return self
 
     def __next__(self) -> T: