diff --git a/lisp/progmodes/make-mode.el b/lisp/progmodes/make-mode.el
index d22aedb6058..a3146df3e45 100644
--- a/lisp/progmodes/make-mode.el
+++ b/lisp/progmodes/make-mode.el
@@ -1304,7 +1304,7 @@ definition and conveniently use this command."
   (save-excursion
     (beginning-of-line)
     (cond
-     ((looking-at "^#+")
+     ((looking-at "^#+\\s-*")
       ;; Found a comment.  Return nil to let normal filling take place.
       nil)