diff --git a/test/functional/plugin/tohtml_spec.lua b/test/functional/plugin/tohtml_spec.lua
index 01013ff407..b4270dfef3 100644
--- a/test/functional/plugin/tohtml_spec.lua
+++ b/test/functional/plugin/tohtml_spec.lua
@@ -260,6 +260,7 @@ describe(':TOhtml', function()
     exec('set termguicolors')
     exec('syntax enable')
     exec('setf lua')
+    exec_lua('vim.treesitter.stop()') -- Ensure that legacy syntax (not just TS) is tested.
     run_tohtml_and_assert(screen)
   end)