diff --git a/common/models/role.js b/common/models/role.js
index 87a7d24c..988d8a79 100644
--- a/common/models/role.js
+++ b/common/models/role.js
@@ -145,12 +145,10 @@ module.exports = function(Role) {
   });
 
   function isUserClass(modelClass) {
-    if (modelClass) {
-      return modelClass === loopback.User ||
-        modelClass.prototype instanceof loopback.User;
-    } else {
-      return false;
-    }
+    if (!modelClass) return false;
+    var User = modelClass.modelBuilder.models.User;
+    if (!User) return false;
+    return modelClass == User || modelClass.prototype instanceof User;
   }
 
   /*!
diff --git a/test/role.test.js b/test/role.test.js
index 8ecddde2..36a18af5 100644
--- a/test/role.test.js
+++ b/test/role.test.js
@@ -434,4 +434,28 @@ describe('role model', function() {
       });
     });
   });
+
+  describe('isOwner', function() {
+    it('supports app-local model registry', function(done) {
+      var app = loopback({ localRegistry: true, loadBuiltinModels: true });
+      app.dataSource('db', { connector: 'memory' });
+      // attach all auth-related models to 'db' datasource
+      app.enableAuth({ dataSource: 'db' });
+
+      var Role = app.models.Role;
+      var User = app.models.User;
+
+      var u = app.registry.findModel('User');
+      var credentials = { email: 'test@example.com', password: 'pass' };
+      User.create(credentials, function(err, user) {
+        if (err) return done(err);
+
+        Role.isOwner(User, user.id, user.id, function(err, result) {
+          if (err) return done(err);
+          expect(result, 'isOwner result').to.equal(true);
+          done();
+        });
+      });
+    });
+  });
 });