diff --git a/runtime/indent/ocaml.vim b/runtime/indent/ocaml.vim
index 19c81f4..c9beb8b 100644
--- a/runtime/indent/ocaml.vim
+++ b/runtime/indent/ocaml.vim
@@ -4,7 +4,8 @@
 "               Mike Leary           <leary@nwlink.com>
 "               Markus Mottl         <markus.mottl@gmail.com>
 " URL:          https://github.com/ocaml/vim-ocaml
-" Last Change:  2017 Jun 13
+" Last Change:  2023 Aug 28 - Add undo_indent (Vim Project)
+"               2017 Jun 13
 "               2005 Jun 25 - Fixed multiple bugs due to 'else\nreturn ind' working
 "               2005 May 09 - Added an option to not indent OCaml-indents specially (MM)
 "               2013 June   - commented textwidth (Marc Weber)
@@ -24,6 +25,8 @@
 setlocal nolisp
 setlocal nosmartindent
 
+let b:undo_indent = "setl et< inde< indk< lisp< si<"
+
 " At least Marc Weber and Markus Mottl do not like this:
 " setlocal textwidth=80