diff --git a/rest_framework/routers.py b/rest_framework/routers.py
index 9ddc49c4f..c25077412 100644
--- a/rest_framework/routers.py
+++ b/rest_framework/routers.py
@@ -27,6 +27,7 @@ from rest_framework.schemas import SchemaGenerator
 from rest_framework.schemas.views import SchemaView
 from rest_framework.settings import api_settings
 from rest_framework.urlpatterns import format_suffix_patterns
+from rest_framework.viewsets import ViewSet
 
 Route = namedtuple('Route', ['url', 'mapping', 'name', 'detail', 'initkwargs'])
 DynamicRoute = namedtuple('DynamicRoute', ['url', 'name', 'detail', 'initkwargs'])