diff --git a/src/marshmallow/schema.py b/src/marshmallow/schema.py
index acf728f..e0a7cae 100644
--- a/src/marshmallow/schema.py
+++ b/src/marshmallow/schema.py
@@ -16,7 +16,7 @@ from marshmallow import base, fields, utils, class_registry, marshalling
 from marshmallow.compat import (with_metaclass, iteritems, text_type,
                                 binary_type, Mapping, OrderedDict)
 from marshmallow.exceptions import ValidationError
-from marshmallow.orderedset import OrderedSet
+from ordered_set import OrderedSet
 from marshmallow.decorators import (PRE_DUMP, POST_DUMP, PRE_LOAD, POST_LOAD,
                                     VALIDATES, VALIDATES_SCHEMA)
 from marshmallow.utils import missing