diff --git a/highlighting/highlightjs_carbon_lang.js b/highlighting/highlightjs_carbon_lang.js
index 5830ad3f4880..a17ab6d6450b 100644
--- a/highlighting/highlightjs_carbon_lang.js
+++ b/highlighting/highlightjs_carbon_lang.js
@@ -449,7 +449,7 @@ export default function (hljs) {
     beginScope: 'punctuation',
     end: /\}/,
     endScope: 'punctuation',
-    contains: ['self', ...STATEMENTS],
+    contains: ['self', hljs.C_LINE_COMMENT_MODE, ...STATEMENTS],
   };
 
   // Stitch everything together into the language definition.