diff --git a/underscore.js b/underscore.js
index f2c8c94b7..fd9ea3d08 100644
--- a/underscore.js
+++ b/underscore.js
@@ -56,6 +56,14 @@
       exports = module.exports = _;
     }
     exports._ = _;
+  } else if (typeof define === 'function' && define.amd) {
+    // Register as a module with AMD. Use a named module since underscore
+    // can be used in optimization schemes that do not understand anonymous
+    // modules, and the if it is used on a page with an AMD loader, a load
+    // error could occur.
+    define('underscore', function() {
+      return _;
+    });
   } else {
     // Exported as a string, for Closure Compiler "advanced" mode.
     root['_'] = _;