diff --git a/mrbgems/mruby-enum-ext/mrblib/enum.rb b/mrbgems/mruby-enum-ext/mrblib/enum.rb
index 0848ab9f6..5f8d82db5 100644
--- a/mrbgems/mruby-enum-ext/mrblib/enum.rb
+++ b/mrbgems/mruby-enum-ext/mrblib/enum.rb
@@ -895,4 +895,8 @@ class Array
     end
     ary.collect!{|e,i| self[i]}
   end
+
+  def sort_by!(&block)
+    self.replace(self.sort_by(&block))
+  end
 end