diff --git a/runtime/ftplugin/groff.vim b/runtime/ftplugin/groff.vim
new file mode 100644
index 0000000..3ebfa03
--- /dev/null
+++ b/runtime/ftplugin/groff.vim
@@ -0,0 +1,15 @@
+" Vim syntax file
+" Language:  groff(7)
+" Maintainer: Eisuke Kawashima ( e.kawaschima+vim AT gmail.com )
+" Last Change: 2025 Apr 24
+
+if exists('b:did_ftplugin')
+  finish
+endif
+
+let b:nroff_is_groff = 1
+
+runtime! ftplugin/nroff.vim
+
+let b:undo_ftplugin .= '| unlet! b:nroff_is_groff'
+let b:did_ftplugin = 1