diff --git a/requirements.txt b/requirements.txt
index eac3504f0f7..244f722217f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -21,7 +21,7 @@ SQLAlchemy>=0.7.8,<=0.8.99
 WebOb>=1.2.3
 python-keystoneclient>=0.6.0
 alembic>=0.4.1
-six>=1.4.1
+six>=1.5.2
 stevedore>=0.14
 oslo.config>=1.2.0
 oslo.rootwrap