diff --git a/Casks/opera-developer.rb b/Casks/opera-developer.rb
index 4589a51d8..42c2b381a 100644
--- a/Casks/opera-developer.rb
+++ b/Casks/opera-developer.rb
@@ -4,6 +4,7 @@ class OperaDeveloper < Cask
 
   url "http://get.geo.opera.com/pub/opera-developer/#{version}/mac/Opera_Developer_#{version}_Setup.dmg"
   homepage 'http://www.opera.com/developer'
+  license :unknown
 
   app 'Opera Developer.app'
 end