diff --git a/lisp/simple.el b/lisp/simple.el
index b48f46fc711..c798ee010b1 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -4061,7 +4061,7 @@ REASON describes the reason that the boundary is being added; see
 (defun undo-auto--boundaries (cause)
   "Check recently changed buffers and add a boundary if necessary.
 REASON describes the reason that the boundary is being added; see
-`undo-last-boundary' for more information."
+`undo-auto--last-boundary-cause' for more information."
   ;; (Bug #23785) All commands should ensure that there is an undo
   ;; boundary whether they have changed the current buffer or not.
   (when (eq cause 'command)