diff --git a/doc/lispref/keymaps.texi b/doc/lispref/keymaps.texi
index a207b0cbb9d..9fd98c73fa4 100644
--- a/doc/lispref/keymaps.texi
+++ b/doc/lispref/keymaps.texi
@@ -1110,7 +1110,7 @@ are used before @code{minor-mode-map-alist} and
 @end defvar
 
 @cindex transient keymap
-@defun set-transient-map keymap &optional keep-pred on-exit
+@defun set-transient-map keymap &optional keep-pred on-exit message timeout
 This function adds @var{keymap} as a @dfn{transient} keymap, which
 takes precedence over other keymaps for one (or more) subsequent keys.