diff --git a/lib/postal.rb b/lib/postal.rb
index 1ddab62..2a0ecbf 100644
--- a/lib/postal.rb
+++ b/lib/postal.rb
@@ -25,6 +25,7 @@ module Postal
     autoload :RspecHelpers
     autoload :SendResult
     autoload :Sender
+    autoload :SMTPSender
     autoload :SMTPServer
     autoload :SpamCheck
     autoload :UserCreator