diff --git a/python/google/protobuf/__init__.py b/python/google/protobuf/__init__.py
index 97ac28028..8b7585d9d 100644
--- a/python/google/protobuf/__init__.py
+++ b/python/google/protobuf/__init__.py
@@ -31,3 +31,9 @@
 # Copyright 2007 Google Inc. All Rights Reserved.

 __version__ = '4.21.5'
+
+if __name__ != '__main__':
+  try:
+    __import__('pkg_resources').declare_namespace(__name__)
+  except ImportError:
+    __path__ = __import__('pkgutil').extend_path(__path__, __name__)