diff --git a/trytond/tools/timezone.py b/trytond/tools/timezone.py
index faa8cc5d55..ca62e4fe18 100644
--- a/trytond/tools/timezone.py
+++ b/trytond/tools/timezone.py
@@ -8,6 +8,7 @@ try:
     ZoneInfo = zoneinfo.ZoneInfo
     ZoneInfoNotFoundError = zoneinfo.ZoneInfoNotFoundError
 except ImportError:
+    zoneinfo = None
     import pytz
     from dateutil.tz import gettz as ZoneInfo