diff --git a/setup.py b/setup.py
index a3cc055c..6310a1bc 100644
--- a/setup.py
+++ b/setup.py
@@ -63,7 +63,7 @@ try:
         'mock',
         'itsdangerous',
         'pytz',
-        'six',
+        'six>=1.4.1',
         'oauthlib==0.5.0',
         'unidecode',