diff --git a/modules/languages/siren-lua.el b/modules/languages/siren-lua.el
index 6d9ecf8..f6fe2c8 100644
--- a/modules/languages/siren-lua.el
+++ b/modules/languages/siren-lua.el
@@ -26,6 +26,7 @@
 
   :preface
   (defun siren-lsp-lua-mode-setup ()
+    (setq-local tab-width 4)
     (lsp-deferred)))
 
 (provide 'siren-lua)