diff --git a/doc/usage.md b/doc/usage.md
index 84917bc0b0..5ada37f79b 100644
--- a/doc/usage.md
+++ b/doc/usage.md
@@ -208,7 +208,7 @@ result.ast;
 
 ### Require hook
 
-All subsequent files required by node with the extensions `.es6` and `.js` will
+All subsequent files required by node with the extensions `.es6`, `.es` and `.js` will
 be transformed by 6to5. The polyfill specified in [Polyfill](polyfill.md) is
 also required; but this is automatically loaded when using: