diff --git a/lib/pretty_text.rb b/lib/pretty_text.rb
index 85ba6df90b5..66792e18d8f 100644
--- a/lib/pretty_text.rb
+++ b/lib/pretty_text.rb
@@ -68,7 +68,7 @@ module PrettyText
         apply_es6_file(ctx, root_path, Regexp.last_match[2])
       elsif l =~ /\/\/= require_tree (\.\/)?(.*)$/
         path = Regexp.last_match[2]
-        Dir["#{root_path}/#{path}/**"].each do |f|
+        Dir["#{root_path}/#{path}/**"].sort.each do |f|
           apply_es6_file(ctx, root_path, f.sub(root_path, '')[1..-1].sub(/\.js.es6$/, ''))
         end
       end