diff --git a/Library/Homebrew/brew.rb b/Library/Homebrew/brew.rb
index 5ca3ee4f0c..d9fd4d2a3e 100644
--- a/Library/Homebrew/brew.rb
+++ b/Library/Homebrew/brew.rb
@@ -2,6 +2,7 @@
 # frozen_string_literal: true
 
 if ENV["HOMEBREW_STACKPROF"]
+  require "rubygems"
   require "stackprof"
   StackProf.start(mode: :wall, raw: true)
 end