diff --git a/requirements.txt b/requirements.txt
index 6b3a459c4..bc729cf8c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,6 +10,6 @@ oslo.utils>=1.2.0                       # Apache-2.0
 PrettyTable>=0.7,<0.8
 requests>=2.2.0,!=2.4.0
 simplejson>=2.2.0
-six>=1.7.0
+six>=1.9.0
 Babel>=1.3
 python-keystoneclient>=1.1.0