diff --git a/Casks/middleclick-snowleopard.rb b/Casks/middleclick-snowleopard.rb
index 2739a35fe..07a3ccc0d 100644
--- a/Casks/middleclick-snowleopard.rb
+++ b/Casks/middleclick-snowleopard.rb
@@ -4,6 +4,7 @@ class MiddleclickSnowleopard < Cask
 
   url 'http://clement.beffa.org/labs/downloads/MiddleClick.zip'
   homepage 'http://clement.beffa.org/labs/projects/middleclick'
+  license :unknown
 
   app 'MiddleClick.app'
 end