diff --git a/pre-upload.py b/pre-upload.py
index c1c49ad..04d13c8 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -16,12 +16,12 @@
 import datetime
 import fnmatch
 import functools
+import io
 import json
 import os
 import re
 import sys
 import stat
-import StringIO
 
 from six.moves import configparser
 
@@ -1569,7 +1569,7 @@
       # commit diff, rather than whatever's on disk.
       # TODO(vapier): Once we migrate this to Python 3 only, cut it over.
       contents = _get_file_content(f, commit)
-      parser.readfp(StringIO.StringIO(contents))
+      parser.readfp(io.StringIO(contents))
     except configparser.Error as e:
       msg = ('Unable to parse COMMIT-QUEUE.ini file at %s due to %s.' %
              (f, e))
diff --git a/pre-upload_unittest.py b/pre-upload_unittest.py
index da27cba..9608cc3 100755
--- a/pre-upload_unittest.py
+++ b/pre-upload_unittest.py
@@ -424,13 +424,13 @@
 
   def testIgnoreIrrelevantFile(self):
     self.file_mock.return_value = ['unrelated_file.ini']
-    self.content_mock.return_value = '^$malformed gibberish^^&'
+    self.content_mock.return_value = u'^$malformed gibberish^^&'
     self.assertEqual(pre_upload._check_cq_ini_well_formed('PROJECT', 'COMMIT'),
                      None)
 
   def testWellformedFile(self):
     self.file_mock.return_value = ['COMMIT-QUEUE.ini']
-    self.content_mock.return_value = """#
+    self.content_mock.return_value = u"""#
 # Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
@@ -450,7 +450,7 @@
 
   def testMalformedFile(self):
     self.file_mock.return_value = ['COMMIT-QUEUE.ini']
-    self.content_mock.return_value = '^$malformed gibberish^^&'
+    self.content_mock.return_value = u'^$malformed gibberish^^&'
     m = pre_upload._check_cq_ini_well_formed('PROJECT', 'COMMIT')
     self.assertTrue(isinstance(m, pre_upload.HookFailure))