diff --git a/pre-upload.py b/pre-upload.py
index 5cd9414..e9b1f06 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -83,6 +83,9 @@
 
     # Ignore license files as the content is often taken verbatim.
     r".*/licenses/.*",
+
+    # Exclude generated python protobuf files.
+    r".*_pb2\.py$",
 ]
 
 LICENSE_EXCLUDED_PATHS = [