diff --git a/bson/tz_util.py b/bson/tz_util.py
index ed5b626ef..7a99b8109 100644
--- a/bson/tz_util.py
+++ b/bson/tz_util.py
@@ -62,3 +62,4 @@ def _UTC():
     module global.
     """
     return utc
+_UTC.__safe_for_unpickling__ = True