diff --git a/grommet-toolbox.config.js b/grommet-toolbox.config.js
index 0b41bf43c8a..d100e2ac6b7 100644
--- a/grommet-toolbox.config.js
+++ b/grommet-toolbox.config.js
@@ -88,7 +88,8 @@ export default {
     },
     externals: {
       'react': 'React',
-      'react-dom': 'ReactDOM'
+      'react-dom': 'ReactDOM',
+      'react-addons-transition-group': 'React.addons.TransitionGroup'
     }
   },
   distPreprocess: ['generate-index-icons', 'dist-css'],