diff --git a/Library/Homebrew/cmd/doctor.rb b/Library/Homebrew/cmd/doctor.rb
index 1d46405b9e..41f952b1ed 100644
--- a/Library/Homebrew/cmd/doctor.rb
+++ b/Library/Homebrew/cmd/doctor.rb
@@ -1,4 +1,3 @@
-require 'set'
 require 'cmd/missing'
 
 class Volumes
diff --git a/Library/Homebrew/dependencies.rb b/Library/Homebrew/dependencies.rb
index 8407a7a70b..c4b8f0b671 100644
--- a/Library/Homebrew/dependencies.rb
+++ b/Library/Homebrew/dependencies.rb
@@ -1,5 +1,3 @@
-require 'set'
-
 ## This file defines dependencies and requirements.
 ##
 ## A dependency is a formula that another formula needs to install.
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 8f4f1b799e..bb9b7e2306 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -1,7 +1,6 @@
 require 'exceptions'
 require 'formula'
 require 'keg'
-require 'set'
 require 'tab'
 require 'bottles'
 
diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index a8dd3b04e1..4bd8723cc0 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -3,6 +3,7 @@ require 'extend/ARGV'
 require 'extend/string'
 require 'utils'
 require 'exceptions'
+require 'set'
 
 ARGV.extend(HomebrewArgvExtension)