diff --git a/lib/builder.js b/lib/builder.js
index 764d03b..d8735a3 100644
--- a/lib/builder.js
+++ b/lib/builder.js
@@ -282,7 +282,7 @@ function executeConfigFile(saveForReset, ignoreBaseURL, configPath, source) {
   // only substitute local copy of System
   // and prevent that code from adding anything to the real global 
   var context = Object.create(global);
-  context.System = configLoader;
+  context.SystemJS = context.System = configLoader;
   context.global = context.GLOBAL = context.root = context;
   // make require available too, make it look as if config file was
   // loaded like a module