diff --git a/.travis.yml b/.travis.yml
index 7832fda8000335c1d3242182b32de762f3f364eb..87b99925874ef9a5fcb8504019eabacd44cc0232 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,7 @@
 language: python
 python: "2.7"
 install:
+  - "pip install six"
   - "make install"
 sudo: false
 script: