diff --git a/testem.js b/testem.js
index ed2f371..ce64b47 100644
--- a/testem.js
+++ b/testem.js
@@ -3,7 +3,7 @@
 module.exports = {
   test_page: 'tests/index.html?hidepassed',
   disable_watching: true,
-  launch_in_ci: ['Chrome'],
+  launch_in_ci: ['Chrome', 'Firefox'],
   launch_in_dev: ['Chrome'],
   browser_start_timeout: 120,
   browser_args: {