diff --git a/etc/requirements.txt b/etc/requirements.txt
index 94577578..2b60f394 100644
--- a/etc/requirements.txt
+++ b/etc/requirements.txt
@@ -16,3 +16,5 @@ TA-Lib==0.4.8
 
 # For fetching remote data
 requests==2.2.0
+
+six==1.6.1
diff --git a/setup.py b/setup.py
index 0ab21251..09a58afd 100644
--- a/setup.py
+++ b/setup.py
@@ -67,7 +67,8 @@ setup(
         'pytz',
         'requests',
         'numpy',
-        'pandas'
+        'pandas',
+        'six'
     ],
     url="https://github.com/quantopian/zipline"
 )