diff --git a/tastypie_oauth/authentication.py b/tastypie_oauth/authentication.py
index e30dfb4..5ef2aae 100644
--- a/tastypie_oauth/authentication.py
+++ b/tastypie_oauth/authentication.py
@@ -6,7 +6,6 @@
 from django.contrib.auth.models import AnonymousUser
 from django.utils import timezone
 from tastypie.authentication import Authentication
-from tastypie.http import HttpUnauthorized
 
 """
 This is a simple OAuth 2.0 authentication model for tastypie
@@ -64,7 +63,7 @@ def is_authenticated(self, request, **kwargs):
 
             # If OAuth authentication is successful, set the request user to
             # the token user for authorization
-            request.user = token.user
+            request.user = token.user or AnonymousUser()
 
             # If OAuth authentication is successful, set oauth_consumer_key on
             # request in case we need it later