diff --git a/src/compiler/compile/render_dom/index.ts b/src/compiler/compile/render_dom/index.ts
index 590b0fe65c..b4b96ce42e 100644
--- a/src/compiler/compile/render_dom/index.ts
+++ b/src/compiler/compile/render_dom/index.ts
@@ -49,7 +49,7 @@ export default function dom(
 
 	const should_add_css = (
 		!!styles &&
-		options.css === 'injected'
+		(options.customElement || options.css === 'injected')
 	);
 
 	if (should_add_css) {