diff --git a/.travis.yml b/.travis.yml
index 411ce7e..00aed3b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,7 @@ python:
     - pypy
 install:
   - pip install coveralls
+  - pip install tox
 script:
   coverage run --source=untangle ./setup.py test