diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9509cc0..53f17c9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,3 +21,5 @@ jobs:
         run: pip install "setuptools<81" vim-vint
       - name: Lint Vimscript
         run: vint ftdetect ftplugin syntax
+      - name: Test regex highlighting
+        run: vim -Nu NONE -n -es -S tests/regex_syntax.vim
diff --git a/syntax/sema.vim b/syntax/sema.vim
index 4298eb9..12abdd6 100644
--- a/syntax/sema.vim
+++ b/syntax/sema.vim
@@ -18,6 +18,7 @@ syn keyword semaTodo TODO FIXME XXX HACK NOTE contained
 
 " ---------- Strings & Characters ----------------------------------------
 
+syn region semaRegex start=/#"/ skip=/\\./ end=/"/
 syn region semaString start=/"/ skip=/\\./ end=/"/ contains=semaStringEscape
 syn match semaStringEscape /\\./ contained
 
@@ -496,6 +497,7 @@ hi def link semaComment Comment
 hi def link semaBlockComment Comment
 hi def link semaTodo Todo
 hi def link semaString String
+hi def link semaRegex String
 hi def link semaStringEscape SpecialChar
 hi def link semaNumber Number
 hi def link semaBoolean Boolean
diff --git a/tests/regex_syntax.vim b/tests/regex_syntax.vim
new file mode 100644
index 0000000..2a94915
--- /dev/null
+++ b/tests/regex_syntax.vim
@@ -0,0 +1,27 @@
+set nocompatible
+set runtimepath^=.
+syntax on
+
+new
+setfiletype sema
+call setline(1, '(regex/match? #"\d+" "123")')
+call setline(2, '(regex/match? #"\"[^\"]+\"" text)')
+call setline(3, '(regex/match? #"\\" text)')
+
+function! AssertGroup(line, column, expected) abort
+  let actual = synIDattr(synID(a:line, a:column, 1), 'name')
+  if actual !=# a:expected
+    echom printf('%d:%d expected %s, got %s', a:line, a:column, a:expected, actual)
+    cquit 1
+  endif
+endfunction
+
+call AssertGroup(1, 2, 'semaBuiltin')
+call AssertGroup(1, 15, 'semaRegex')
+call AssertGroup(1, 17, 'semaRegex')
+call AssertGroup(2, 15, 'semaRegex')
+call AssertGroup(2, 18, 'semaRegex')
+call AssertGroup(3, 15, 'semaRegex')
+call AssertGroup(3, 17, 'semaRegex')
+
+quitall!