diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index 4980fde3d5..b8643aa6d5 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -43,7 +43,8 @@ module OS
               path = bundle_path
               path.join("Contents", "Developer") if path
             else
-              Pathname.new(dir)
+              # Use cleanpath to avoid pathological trailing slash
+              Pathname.new(dir).cleanpath
             end
           end
       end