diff --git a/Casks/x-moto.rb b/Casks/x-moto.rb
index 59de6badad1..f859ed3a3c0 100644
--- a/Casks/x-moto.rb
+++ b/Casks/x-moto.rb
@@ -4,6 +4,7 @@ class XMoto < Cask
 
   url "http://download.tuxfamily.org/xmoto/xmoto/#{version}/xmoto-#{version}-macosx.zip"
   homepage 'http://xmoto.tuxfamily.org'
+  license :unknown
 
   app 'X-Moto.app'
 end