diff --git a/runtime/syntax/ondir.vim b/runtime/syntax/ondir.vim
new file mode 100644
index 0000000..4aeb014
--- /dev/null
+++ b/runtime/syntax/ondir.vim
@@ -0,0 +1,35 @@
+" Vim syntax file
+" Language:     ondir <https://github.com/alecthomas/ondir>
+" Maintainer:   Jon Parise <jon@indelible.org>
+
+if exists('b:current_syntax')
+  finish
+endif
+
+let s:cpo_save = &cpoptions
+set cpoptions&vim
+
+syn case match
+
+syn match   ondirComment  "#.*" contains=@Spell
+syn keyword ondirKeyword  final contained skipwhite nextgroup=ondirKeyword
+syn keyword ondirKeyword  enter leave contained skipwhite nextgroup=ondirPath
+syn match   ondirPath     "[^:]\+" contained display
+syn match   ondirColon    ":" contained display
+
+syn include @ondirShell   syntax/sh.vim
+syn region  ondirContent  start="^\s\+" end="^\ze\S.*$" keepend contained contains=@ondirShell
+
+syn region  ondirSection  start="^\(final\|enter\|leave\)" end="^\ze\S.*$" fold contains=ondirKeyword,ondirPath,ondirColon,ondirContent
+
+hi def link ondirComment  Comment
+hi def link ondirKeyword  Keyword
+hi def link ondirPath     Special
+hi def link ondirColon    Operator
+
+let b:current_syntax = 'ondir'
+
+let &cpoptions = s:cpo_save
+unlet s:cpo_save
+
+" vim: et ts=4 sw=2 sts=2: