diff --git a/requirements.txt b/requirements.txt
index d35d66847..89945bd9d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,7 +19,7 @@ python-novaclient>=2.18.0
 python-neutronclient>=2.3.6,<3
 python-swiftclient>=2.2.0
 python-ceilometerclient>=1.0.6
-pytz
+pytz>=2013.6
 # Horizon Utility Requirements
 # for SECURE_KEY generation
 lockfile>=0.8