diff --git a/runtime/ftplugin/spec.vim b/runtime/ftplugin/spec.vim
index fa125be..dcf2908 100644
--- a/runtime/ftplugin/spec.vim
+++ b/runtime/ftplugin/spec.vim
@@ -5,6 +5,7 @@
 " Last Change: 2015 Jun 01
 "  Update by Zdenek Dohnal, 2022 May 17
 "  2024 Sep 10 by Vim Project: add epoch support for spec changelog, #15537
+"  2024 Oct 07 by Vim Project: add comment support, #15817
 
 if exists("b:did_ftplugin")
 	finish
@@ -14,6 +15,11 @@
 let s:cpo_save = &cpo
 set cpo&vim
 
+setlocal comments=b:#
+setlocal commentstring=#\ %s
+
+let b:undo_ftplugin = "setlocal comments< commentstring<"
+
 if !exists("no_plugin_maps") && !exists("no_spec_maps")
 	if !hasmapto("<Plug>SpecChangelog")
 		map <buffer> <LocalLeader>c <Plug>SpecChangelog
@@ -216,4 +222,4 @@
 let &cpo = s:cpo_save
 unlet s:cpo_save
 
-let b:undo_ftplugin = "unlet! b:match_ignorecase b:match_words"
+let b:undo_ftplugin ..= " | unlet! b:match_ignorecase b:match_words"