diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index 8726fa1a40c1a559041ffec1bd0d65fc722bb83a..05af5bb6704cbf83a6d9291e270fd10a8308a1e4 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -53,6 +53,7 @@ HOMEBREW_PULL_OR_COMMIT_URL_REGEX = %r[https://github\.com/([\w-]+)/([\w-]+)?/(?
 
 require "compat" unless ARGV.include?("--no-compat") || ENV["HOMEBREW_NO_COMPAT"]
 
+ENV["HOMEBREW_PATH"] ||= ENV["PATH"]
 ORIGINAL_PATHS = ENV["HOMEBREW_PATH"].split(File::PATH_SEPARATOR).map do |p|
   begin
     Pathname.new(p).expand_path