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
diff --git a/runtime/ftplugin/nroff.vim b/runtime/ftplugin/nroff.vim
index 1c6d4eb..cd2680e 100644
--- a/runtime/ftplugin/nroff.vim
+++ b/runtime/ftplugin/nroff.vim
@@ -8,6 +8,7 @@
 "	2024 May 24 by Riley Bruins <ribru17@gmail.com> ('commentstring' #14843)
 "	2025 Feb 12 by Wu, Zhenyu <wuzhenyu@ustc.edu> (matchit configuration #16619)
 "	2025 Apr 16 by Eisuke Kawashima (cpoptions #17121)
+"	2025 Apr 24 by Eisuke Kawashima (move options from syntax to ftplugin #17174)
 
 if exists("b:did_ftplugin")
   finish
@@ -22,7 +23,17 @@
 setlocal sections+=Sh
 setlocal define=.\s*de
 
-let b:undo_ftplugin = 'setlocal commentstring< comments< sections< define<'
+if get(b:, 'preprocs_as_sections')
+  setlocal sections=EQTSPS[\ G1GS
+endif
+
+let b:undo_ftplugin = 'setlocal commentstring< comments< sections& define<'
+
+if get(b:, 'nroff_is_groff')
+  " groff_ms exdented paragraphs are not in the default paragraphs list.
+  setlocal paragraphs+=XP
+  let b:undo_ftplugin .= ' paragraphs&'
+endif
 
 if exists('loaded_matchit')
   let b:match_words = '^\.\s*ie\>:^\.\s*el\>'
diff --git a/runtime/syntax/nroff.vim b/runtime/syntax/nroff.vim
index 5667042..fec966f 100644
--- a/runtime/syntax/nroff.vim
+++ b/runtime/syntax/nroff.vim
@@ -4,6 +4,7 @@
 " Previous Maintainer:	Pedro Alejandro López-Valencia <palopezv@gmail.com>
 " Previous Maintainer:	Jérôme Plût <Jerome.Plut@ens.fr>
 " Last Change:	2021 Mar 28
+"	2025 Apr 24 by Eisuke Kawashima (move options from syntax to ftplugin #17174)
 "
 " {{{1 Todo
 "
@@ -40,19 +41,6 @@
 	syn match nroffError /\s\+$/
 	syn match nroffSpaceError /[.,:;!?]\s\{2,}/
 endif
-"
-"
-" {{{1 Special file settings
-"
-" {{{2  ms exdented paragraphs are not in the default paragraphs list.
-"
-setlocal paragraphs+=XP
-"
-" {{{2 Activate navigation to preprocessor sections.
-"
-if exists("b:preprocs_as_sections")
-	setlocal sections=EQTSPS[\ G1GS
-endif
 
 " {{{1 Escape sequences
 " ------------------------------------------------------------