diff --git a/lib/multimarkdown-cli/tilt_plugin.rb b/lib/multimarkdown-cli/tilt_plugin.rb
index <HASH>..<HASH> 100644
--- a/lib/multimarkdown-cli/tilt_plugin.rb
+++ b/lib/multimarkdown-cli/tilt_plugin.rb
@@ -27,7 +27,7 @@ module MultiMarkdownCLI
     end
   end
 
-  Tilt.register Template, 'multimarkdown'
+  Tilt.register Template, 'multimarkdown', 'mmd'
 end
add mmd as a valid extension