diff --git a/lib/rack/handler/puma.rb b/lib/rack/handler/puma.rb
index 0bf06456..3ff18958 100644
--- a/lib/rack/handler/puma.rb
+++ b/lib/rack/handler/puma.rb
@@ -9,6 +9,7 @@ module Rack
       }
 
       def self.config(app, options = {})
+        require 'puma'
         require 'puma/configuration'
         require 'puma/events'
         require 'puma/launcher'