diff --git a/actionmailer/lib/action_mailer/test_helper.rb b/actionmailer/lib/action_mailer/test_helper.rb
index 87d12ec2c7..06da0dd27e 100644
--- a/actionmailer/lib/action_mailer/test_helper.rb
+++ b/actionmailer/lib/action_mailer/test_helper.rb
@@ -1,5 +1,5 @@
 module ActionMailer
-  # Provides helper methods for testing ActionMailer, including #assert_emails
+  # Provides helper methods for testing Action Mailer, including #assert_emails
   # and #assert_no_emails
   module TestHelper
     # Asserts that the number of emails sent matches the given number.