diff --git a/lib/internal/modules/esm/get_format.js b/lib/internal/modules/esm/get_format.js
index f02bb5cde70772..9ee7d473a74ef2 100644
--- a/lib/internal/modules/esm/get_format.js
+++ b/lib/internal/modules/esm/get_format.js
@@ -56,7 +56,7 @@ function defaultGetFormat(url, context, defaultGetFormatUnused) {
   } else if (parsed.protocol === 'file:') {
     const ext = extname(parsed.pathname);
     let format;
-    if (ext === '.js') {
+    if (ext === '.js' || ext === '') {
       format = getPackageType(parsed.href) === 'module' ? 'module' : 'commonjs';
     } else {
       format = extensionFormatMap[ext];