diff --git a/setup.py b/setup.py
index 3d2c1f07620bb7e05bab79aebdf2c7f8c38055a9..2da4d33acd53533f26bd866b0105d75a4a54fc29 100644
--- a/setup.py
+++ b/setup.py
@@ -46,6 +46,7 @@ def main():
               "Mako>=0.7.3",
               "pytest>=2.3",
               "cgen>=2013.1.2",
+              "six",
               ])