diff --git a/knox/auth.py b/knox/auth.py
index c013c4dd..8f9d3bc6 100644
--- a/knox/auth.py
+++ b/knox/auth.py
@@ -14,7 +14,6 @@ def compare_digest(a, b):
 )
 
 from knox.crypto import hash_token
-from knox.models import AuthToken
 from knox.settings import CONSTANTS, knox_settings
 from knox.signals import token_expired
 
@@ -31,7 +30,13 @@ class TokenAuthentication(BaseAuthentication):
     - `request.user` will be a django `User` instance
     - `request.auth` will be an `AuthToken` instance
     '''
-    model = AuthToken
+    model = None
+
+    def get_model(self):
+        if self.model is not None:
+            return self.model
+        from knox.models import AuthToken
+        return AuthToken
 
     def authenticate(self, request):
         auth = get_authorization_header(request).split()
@@ -62,7 +67,7 @@ def authenticate_credentials(self, token):
         '''
         msg = _('Invalid token.')
         token = token.decode("utf-8")
-        for auth_token in AuthToken.objects.filter(
+        for auth_token in self.get_model().objects.filter(
                 token_key=token[:CONSTANTS.TOKEN_KEY_LENGTH]):
             if self._cleanup_token(auth_token):
                 continue