diff --git a/requirements.txt b/requirements.txt
index 2e5c12998..4095c8454 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ stevedore>=0.14
 iso8601>=0.1.9
 
 # for jsonutils
-six>=1.5.2
+six>=1.6.0
 
 # FIXME(markmc): remove this when the drivers no longer
 # import eventlet