diff --git a/.travis.yml b/.travis.yml
index a111809f..9f512382 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,10 @@ python:
   - "pypy"
   - "pypy3"
 install: "pip install -r requirements/core.txt;pip install -r requirements/test.txt"
+os:
+  - linux
+  - osx
+  - windows
 addons:
   srcclr: true
 script: "nosetests --with-coverage --cover-package=optimizely"