--- a/dulwich/contrib/test_swift.py
+++ b/dulwich/contrib/test_swift.py
@@ -58,9 +58,12 @@ except ImportError:
     missing_libs.append("geventhttpclient")
 
 try:
-    from mock import patch
+    from unittest.mock import patch
 except ImportError:
-    missing_libs.append("mock")
+    try:
+        from mock import patch
+    except ImportError:
+        missing_libs.append("mock")
 
 skipmsg = "Required libraries are not installed (%r)" % missing_libs
 
--- a/dulwich/tests/test_archive.py
+++ b/dulwich/tests/test_archive.py
@@ -41,9 +41,12 @@ from dulwich.tests.utils import (
     )
 
 try:
-    from mock import patch
+    from unittest.mock import patch
 except ImportError:
-    patch = None   # type: ignore
+    try:
+        from mock import patch
+    except ImportError:
+        patch = None  # type: ignore
 
 
 class ArchiveTests(TestCase):
--- a/setup.py
+++ b/setup.py
@@ -62,7 +62,7 @@ tests_require = ['fastimport']
 
 if '__pypy__' not in sys.modules and not sys.platform == 'win32':
     tests_require.extend([
-        'gevent', 'geventhttpclient', 'mock', 'setuptools>=17.1'])
+        'gevent', 'geventhttpclient', 'setuptools>=17.1'])
 
 
 ext_modules = [