diff --git a/django/core/mail/message.py b/django/core/mail/message.py
index e8d209c9da..9092cce9c1 100644
--- a/django/core/mail/message.py
+++ b/django/core/mail/message.py
@@ -14,6 +14,7 @@ from email.mime.message import MIMEMessage
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
 from email.utils import formataddr, formatdate, getaddresses, parseaddr
+from io import BytesIO
 
 from django.conf import settings
 from django.core.mail.utils import DNS_NAME
@@ -145,7 +146,7 @@ class MIMEMixin():
             This overrides the default as_bytes() implementation to not mangle
             lines that begin with 'From '. See bug #13433 for details.
             """
-            fp = six.BytesIO()
+            fp = BytesIO()
             g = generator.BytesGenerator(fp, mangle_from_=False)
             g.flatten(self, unixfrom=unixfrom, linesep=linesep)
             return fp.getvalue()
diff --git a/tests/file_uploads/tests.py b/tests/file_uploads/tests.py
index e6814aacdf..2fe1499738 100644
--- a/tests/file_uploads/tests.py
+++ b/tests/file_uploads/tests.py
@@ -9,6 +9,7 @@ import os
 import shutil
 import tempfile as sys_tempfile
 import unittest
+from io import BytesIO
 
 from django.core.files import temp as tempfile
 from django.core.files.uploadedfile import SimpleUploadedFile
@@ -16,7 +17,7 @@ from django.http.multipartparser import MultiPartParser, parse_header
 from django.test import SimpleTestCase, TestCase, client, override_settings
 from django.utils.encoding import force_bytes
 from django.utils.http import urlquote
-from django.utils.six import PY2, BytesIO, StringIO
+from django.utils.six import PY2, StringIO
 
 from . import uploadhandler
 from .models import FileModel
diff --git a/tests/servers/test_basehttp.py b/tests/servers/test_basehttp.py
index 91dcaa17d9..b9008be8e8 100644
--- a/tests/servers/test_basehttp.py
+++ b/tests/servers/test_basehttp.py
@@ -1,9 +1,10 @@
+from io import BytesIO
+
 from django.core.handlers.wsgi import WSGIRequest
 from django.core.servers.basehttp import WSGIRequestHandler
 from django.test import SimpleTestCase
 from django.test.client import RequestFactory
 from django.test.utils import captured_stderr
-from django.utils.six import BytesIO
 
 
 class Stub(object):