diff --git a/.travis.yml b/.travis.yml
index 41ca4cf2c3887201dae403a4e65d816de3718d0f..627899947233fd7744a9aa32092aa6364a2921b3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -39,6 +39,6 @@ script:
   # download data and models, then run tests
   - mhcflurry-downloads fetch
   - mhcflurry-downloads info  # just to test this command works
-  - PYTHONHASHSEED=0 nosetests test --with-coverage --cover-package=mhcflurry  && ./lint.sh
+  - KERAS_BACKEND=theano PYTHONHASHSEED=0 nosetests test --with-coverage --cover-package=mhcflurry  && ./lint.sh
 after_success:
   coveralls