diff --git a/wagtail/wagtailcore/models.py b/wagtail/wagtailcore/models.py
index f31e1fe95d..35f40dfff3 100644
--- a/wagtail/wagtailcore/models.py
+++ b/wagtail/wagtailcore/models.py
@@ -3,6 +3,7 @@ from __future__ import absolute_import, unicode_literals
 import json
 import logging
 from collections import defaultdict
+from io import StringIO
 from urllib.parse import urlparse
 
 from django.conf import settings
@@ -22,7 +23,6 @@ from django.urls import reverse
 # Must be imported from Django so we get the new implementation of with_metaclass
 from django.utils import six, timezone
 from django.utils.functional import cached_property
-from django.utils.six import StringIO
 from django.utils.text import capfirst, slugify
 from django.utils.translation import ugettext_lazy as _
 from modelcluster.models import ClusterableModel, get_all_child_relations
diff --git a/wagtail/wagtailcore/tests/test_management_commands.py b/wagtail/wagtailcore/tests/test_management_commands.py
index ebf8412d19..fe83e9ee01 100644
--- a/wagtail/wagtailcore/tests/test_management_commands.py
+++ b/wagtail/wagtailcore/tests/test_management_commands.py
@@ -1,12 +1,12 @@
 from __future__ import absolute_import, unicode_literals
 
 from datetime import timedelta
+from io import StringIO
 
 from django.core import management
 from django.db import models
 from django.test import TestCase
 from django.utils import timezone
-from django.utils.six import StringIO
 
 from wagtail.tests.testapp.models import EventPage, SimplePage
 from wagtail.wagtailcore.models import Page, PageRevision
diff --git a/wagtail/wagtailsearch/tests/elasticsearch_common_tests.py b/wagtail/wagtailsearch/tests/elasticsearch_common_tests.py
index 22b7692f40..bb0c1a2084 100644
--- a/wagtail/wagtailsearch/tests/elasticsearch_common_tests.py
+++ b/wagtail/wagtailsearch/tests/elasticsearch_common_tests.py
@@ -1,9 +1,9 @@
 from __future__ import absolute_import, unicode_literals
 
 from datetime import date
+from io import StringIO
 
 from django.core import management
-from django.utils.six import StringIO
 
 from wagtail.tests.search import models
 
diff --git a/wagtail/wagtailsearch/tests/test_backends.py b/wagtail/wagtailsearch/tests/test_backends.py
index cc4ac78462..7ed7ad0566 100644
--- a/wagtail/wagtailsearch/tests/test_backends.py
+++ b/wagtail/wagtailsearch/tests/test_backends.py
@@ -4,12 +4,12 @@ from __future__ import absolute_import, unicode_literals
 
 import unittest
 from datetime import date
+from io import StringIO
 
 from django.conf import settings
 from django.core import management
 from django.test import TestCase
 from django.test.utils import override_settings
-from django.utils.six import StringIO
 
 from wagtail.tests.search import models
 from wagtail.tests.utils import WagtailTestUtils
diff --git a/wagtail/wagtailsearch/tests/test_queries.py b/wagtail/wagtailsearch/tests/test_queries.py
index c7f0c2f004..140bb40cef 100644
--- a/wagtail/wagtailsearch/tests/test_queries.py
+++ b/wagtail/wagtailsearch/tests/test_queries.py
@@ -1,10 +1,10 @@
 from __future__ import absolute_import, unicode_literals
 
 import datetime
+from io import StringIO
 
 from django.core import management
 from django.test import SimpleTestCase, TestCase
-from django.utils.six import StringIO
 
 from wagtail.contrib.wagtailsearchpromotions.models import SearchPromotion
 from wagtail.tests.utils import WagtailTestUtils