diff --git a/runtime/doc/lsp.txt b/runtime/doc/lsp.txt
index 938e2df3b0..d47d4f6ded 100644
--- a/runtime/doc/lsp.txt
+++ b/runtime/doc/lsp.txt
@@ -1038,7 +1038,7 @@ enable({name}, {enable})                                    *vim.lsp.enable()*
     config to activate: >lua
         vim.lsp.config('lua_ls', {
           root_dir = function(bufnr, on_dir)
-            if not vim.fn.bufname(bufnr):match('%.txt$') then
+            if vim.fs.ext(vim.fn.bufname(bufnr)) ~= 'txt' then
               on_dir(vim.fn.getcwd())
             end
           end
diff --git a/runtime/doc/lua.txt b/runtime/doc/lua.txt
index d5ce2c2209..5ae83df462 100644
--- a/runtime/doc/lua.txt
+++ b/runtime/doc/lua.txt
@@ -2537,6 +2537,28 @@ vim.fs.dirname({file})                                      *vim.fs.dirname()*
     Return: ~
         (`string?`) Parent directory of {file}
 
+vim.fs.ext({file}, {opts})                                      *vim.fs.ext()*
+    Return the file's last extension, if any.
+
+    Similar to |fnamemodify()| with the |::e| modifier. The extension does not
+    include a leading period.
+
+    Examples: >lua
+        vim.fs.ext('archive.tar.gz') -- 'gz'
+        vim.fs.ext('~/.git') -- ''
+        vim.fs.ext('plugin/myplug.lua') -- 'lua'
+<
+
+    Attributes: ~
+        Since: 0.12.0
+
+    Parameters: ~
+      • {file}  (`string`) Path
+      • {opts}  (`table?`) Reserved for future use
+
+    Return: ~
+        (`string`) Extension of {file}
+
 vim.fs.find({names}, {opts})                                   *vim.fs.find()*
     Find files or directories (or other items as specified by `opts.type`) in
     the given path.
@@ -2744,7 +2766,7 @@ vim.fs.root({source}, {marker})                                *vim.fs.root()*
 
         -- Find the parent directory containing any file with a .csproj extension
         vim.fs.root(0, function(name, path)
-          return name:match('%.csproj$') ~= nil
+          return vim.fs.ext(name) == 'csproj'
         end)
 
         -- Find the first ancestor directory containing EITHER "stylua.toml" or ".luarc.json"; if
diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index bf0363d4a4..1f8cd421d7 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -354,6 +354,7 @@ LUA
 • |vim.json.encode()| has an `sort_keys` option.
 • |Range:is_empty()| to check if a |vim.Range| is empty.
 • |vim.json.decode()| has an `skip_comments` option.
+• |vim.fs.ext()| returns the last extension of a file.
 
 OPTIONS
 
diff --git a/runtime/lua/vim/fs.lua b/runtime/lua/vim/fs.lua
index 7eadf8cb78..41e08eeeb2 100644
--- a/runtime/lua/vim/fs.lua
+++ b/runtime/lua/vim/fs.lua
@@ -409,7 +409,7 @@ end
 ---
 --- -- Find the parent directory containing any file with a .csproj extension
 --- vim.fs.root(0, function(name, path)
----   return name:match('%.csproj$') ~= nil
+---   return vim.fs.ext(name) == 'csproj'
 --- end)
 ---
 --- -- Find the first ancestor directory containing EITHER "stylua.toml" or ".luarc.json"; if
@@ -835,4 +835,27 @@ function M.relpath(base, target, opts)
   return vim.startswith(target, base) and target:sub(#base + 1) or nil
 end
 
+--- Return the file's last extension, if any.
+---
+--- Similar to |fnamemodify()| with the |::e| modifier. The extension does not include a leading
+--- period.
+---
+--- Examples:
+---
+--- ```lua
+--- vim.fs.ext('archive.tar.gz') -- 'gz'
+--- vim.fs.ext('~/.git') -- ''
+--- vim.fs.ext('plugin/myplug.lua') -- 'lua'
+--- ```
+---
+---@since 14
+---@param file string Path
+---@param opts table? Reserved for future use
+---@return string Extension of {file}
+function M.ext(file, opts)
+  vim.validate('file', file, 'string')
+  vim.validate('opts', opts, 'table', true)
+  return vim.fn.fnamemodify(file, ':e')
+end
+
 return M
diff --git a/runtime/lua/vim/health.lua b/runtime/lua/vim/health.lua
index e22e72c589..d8f9eb156c 100644
--- a/runtime/lua/vim/health.lua
+++ b/runtime/lua/vim/health.lua
@@ -311,7 +311,7 @@ function M.error(msg, ...)
 end
 
 local path2name = function(path)
-  if path:match('%.lua$') then
+  if vim.fs.ext(path) == 'lua' then
     -- Lua: transform "../lua/vim/lsp/health.lua" into "vim.lsp"
 
     -- Get full path, make sure all slashes are '/'
diff --git a/runtime/lua/vim/lsp.lua b/runtime/lua/vim/lsp.lua
index 3b6f4b4ee2..30ce7eabd8 100644
--- a/runtime/lua/vim/lsp.lua
+++ b/runtime/lua/vim/lsp.lua
@@ -585,7 +585,7 @@ end
 --- ```lua
 --- vim.lsp.config('lua_ls', {
 ---   root_dir = function(bufnr, on_dir)
----     if not vim.fn.bufname(bufnr):match('%.txt$') then
+---     if vim.fs.ext(vim.fn.bufname(bufnr)) ~= 'txt' then
 ---       on_dir(vim.fn.getcwd())
 ---     end
 ---   end
diff --git a/test/functional/lua/fs_spec.lua b/test/functional/lua/fs_spec.lua
index 4d93ce053b..de6e9f1350 100644
--- a/test/functional/lua/fs_spec.lua
+++ b/test/functional/lua/fs_spec.lua
@@ -753,4 +753,10 @@ describe('vim.fs', function()
       assert_rm_symlinked_dir({ recursive = true, force = true })
     end)
   end)
+
+  describe('ext()', function()
+    it('works', function()
+      -- See test/functional/vimscript/fnamemodify_spec.lua
+    end)
+  end)
 end)