diff --git a/Library/Homebrew/rubocops/patches.rb b/Library/Homebrew/rubocops/patches.rb
index 605683eacf..28d3d55fd5 100644
--- a/Library/Homebrew/rubocops/patches.rb
+++ b/Library/Homebrew/rubocops/patches.rb
@@ -69,7 +69,7 @@ module RuboCop
           gh_patch_param_pattern = %r{https?://github\.com/.+/.+/(?:commit|pull)/[a-fA-F0-9]*.(?:patch|diff)}
           if regex_match_group(patch_url_node, gh_patch_param_pattern) && !patch_url.match?(/\?full_index=\w+$/)
             problem "GitHub patches should use the full_index parameter: #{patch_url}?full_index=1" do |corrector|
-              corrector.replace(patch_url_node.source_range, "#{patch_url}?full_index=1")
+              corrector.replace(patch_url_node.source_range, "\"#{patch_url}?full_index=1\"")
             end
           end