diff --git a/Library/Homebrew/cmd/deps.rb b/Library/Homebrew/cmd/deps.rb
index 1f67439108..b5b05ce2e5 100644
--- a/Library/Homebrew/cmd/deps.rb
+++ b/Library/Homebrew/cmd/deps.rb
@@ -4,6 +4,7 @@ require "formula"
 require "ostruct"
 require "cli/parser"
 require "cask/caskroom"
+require "cask_dependent"
 
 module Homebrew
   extend DependenciesHelpers