diff --git a/requirements.txt b/requirements.txt
index bfafab66..9b45bd96 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,5 +10,5 @@ oslo.utils>=1.2.0                       # Apache-2.0
 PrettyTable>=0.7,<0.8
 python-keystoneclient>=1.1.0
 requests>=2.2.0,!=2.4.0
-six>=1.7.0
+six>=1.9.0
 stevedore>=1.1.0  # Apache-2.0