diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 8a8e6a7b..19b51753 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -104,7 +104,7 @@ notmuch-show functions such as
 
 Finally, if this variable is set to nil, no header is
 displayed."
-  :type '(choice (const :tag "No header" ni)
+  :type '(choice (const :tag "No header" nil)
                  (const :tag "Subject" t)
                  (string :tag "Format")
 		 (function :tag "Function"))