diff --git a/lisp/emulation/viper.el b/lisp/emulation/viper.el
index 9d2acac4ce7..ee68f868567 100644
--- a/lisp/emulation/viper.el
+++ b/lisp/emulation/viper.el
@@ -403,7 +403,7 @@ widget."
   :group 'viper-misc)
 
 (defcustom viper-emacs-state-mode-list
-  '(custom-mode
+  '(Custom-mode
 
     dired-mode
     efs-mode