diff --git a/.travis.yml b/.travis.yml
index 9e9c826f..42d594fc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,8 @@
 sudo: false
 install: 
     - pip install tox
-script: 
+    - if [[ $TRAVIS_PYTHON_VERSION == 3.3 ]]; then pip install virtualenv==15.2.0; fi
+script:
     - tox
 language:
     - python