diff --git a/extensions/typescript-basics/package.json b/extensions/typescript-basics/package.json
index 0f493fe3e2e..b3c1b42f7e4 100644
--- a/extensions/typescript-basics/package.json
+++ b/extensions/typescript-basics/package.json
@@ -22,7 +22,9 @@
           "typescript"
         ],
         "extensions": [
-          ".ts"
+          ".ts",
+          ".cts",
+          ".mts"
         ],
         "configuration": "./language-configuration.json"
       },