diff --git a/packages-internal/test-utils/src/setupBabel.js b/packages-internal/test-utils/src/setupBabel.js
index 8b042724d2e6d2..02f5188fccc980 100644
--- a/packages-internal/test-utils/src/setupBabel.js
+++ b/packages-internal/test-utils/src/setupBabel.js
@@ -1,3 +1,3 @@
 require('@babel/register')({
-  extensions: ['.js', '.ts', '.tsx'],
+  extensions: ['.js', '.mjs', '.ts', '.tsx'],
 });