diff --git a/lib/6to5/file.js b/lib/6to5/file.js
index 24b3c7350d..c7222c989f 100644
--- a/lib/6to5/file.js
+++ b/lib/6to5/file.js
@@ -19,7 +19,7 @@ function File(opts) {
 }
 
 File.declarations = ["extends", "class-props", "slice", "apply-constructor",
-                     "tagged-template-literal"];
+                     "tagged-template-literal", "interop-require"];
 
 File.normaliseOptions = function (opts) {
   opts = _.cloneDeep(opts || {});