diff --git a/runtime/lua/vim/_core/system.lua b/runtime/lua/vim/_core/system.lua
index bc00042aba..3ff4bcdc2f 100644
--- a/runtime/lua/vim/_core/system.lua
+++ b/runtime/lua/vim/_core/system.lua
@@ -319,7 +319,8 @@ local function spawn(cmd, opts, on_exit, on_error)
   if is_win then
     local cmd1 = vim.fn.exepath(cmd)
     if cmd1 ~= '' then
-      cmd = cmd1
+      -- Use native separators when launching a resolved Windows executable.
+      cmd = cmd1:gsub('/', '\\')
     end
   end
 
diff --git a/test/functional/lua/system_spec.lua b/test/functional/lua/system_spec.lua
index e7a7448fa7..188d430b7c 100644
--- a/test/functional/lua/system_spec.lua
+++ b/test/functional/lua/system_spec.lua
@@ -130,6 +130,17 @@ describe('vim.system', function()
       n.system_sync({ 'chmod', '+x', 'test.bat' })
       n.system_sync({ './test' })
     end)
+
+    it('launches cmd.exe when shellslash is set', function()
+      n.command('set shellslash')
+      local path = exec_lua([[return vim.fn.exepath('cmd.exe')]])
+      t.neq(nil, path:find('/', 1, true))
+
+      local result = n.system_sync({ 'cmd.exe', '/c', 'echo OK' })
+      eq(0, result.code)
+      eq('OK\r\n', result.stdout)
+      eq('', result.stderr)
+    end)
   end
 
   it('always captures all content of stdout/stderr #30846', function()