diff --git a/git_new_branch.py b/git_new_branch.py
index d61a42d790..856b6eab92 100755
--- a/git_new_branch.py
+++ b/git_new_branch.py
@@ -61,8 +61,8 @@ def main(args):
         run('checkout', '--track', opts.upstream, '-b', opts.branch_name)
     get_or_create_merge_base(opts.branch_name)
   except subprocess2.CalledProcessError as cpe:
-    sys.stdout.write(cpe.stdout)
-    sys.stderr.write(cpe.stderr)
+    sys.stdout.write(cpe.stdout.decode('utf-8', 'replace'))
+    sys.stderr.write(cpe.stderr.decode('utf-8', 'replace'))
     return 1
   sys.stderr.write('Switched to branch %s.\n' % opts.branch_name)
   return 0
diff --git a/git_rename_branch.py b/git_rename_branch.py
index 8a07535f73..d40b606812 100755
--- a/git_rename_branch.py
+++ b/git_rename_branch.py
@@ -42,7 +42,7 @@ def main(args):
         if branch_config(branch, 'remote') == '.':
           set_branch_config(branch, 'merge', 'refs/heads/' + opts.new_name)
   except subprocess2.CalledProcessError as cpe:
-    sys.stderr.write(cpe.stderr)
+    sys.stderr.write(cpe.stderr.decode('utf-8', 'replace'))
     return 1
   return 0
 
diff --git a/tests/git_rebase_update_test.py b/tests/git_rebase_update_test.py
index c2a8c5366e..441bc68ebd 100755
--- a/tests/git_rebase_update_test.py
+++ b/tests/git_rebase_update_test.py
@@ -1,10 +1,13 @@
-#!/usr/bin/env python
+#!/usr/bin/env vpython3
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Unit tests for git_rebase_update.py"""
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 import sys
 
@@ -24,7 +27,7 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
   @classmethod
   def getRepoContent(cls, commit):
     # Every commit X gets a file X with the content X
-    return {commit: {'data': commit}}
+    return {commit: {'data': commit.encode('utf-8')}}
 
   @classmethod
   def setUpClass(cls):
@@ -119,7 +122,7 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
     self.assertEqual(self.repo['E'], self.origin['E'])
 
     with self.repo.open('bob', 'wb') as f:
-      f.write('testing auto-freeze/thaw')
+      f.write(b'testing auto-freeze/thaw')
 
     output, _ = self.repo.capture_stdio(self.reup.main)
     self.assertIn('Cannot rebase-update', output)
@@ -158,7 +161,7 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
     self.assertIn('sub_K up-to-date', output)
 
     with self.repo.open('bob') as f:
-      self.assertEqual('testing auto-freeze/thaw', f.read())
+      self.assertEqual(b'testing auto-freeze/thaw', f.read())
 
     self.assertEqual(self.repo.git('status', '--porcelain').stdout, '?? bob\n')