diff --git a/setup.py b/setup.py
index a529ec3f5..0baa95e5b 100644
--- a/setup.py
+++ b/setup.py
@@ -26,7 +26,6 @@
     "coverage==5.*,>=5.0.3",
     "flake8==3.*,>=3.7.9",
     "isort==4.*,>=4.3.21",
-    "mock==3.*,>=3.0.5",
     "numpy==1.*,>=1.18.1",
     "preggy==1.*,>=1.4.4",
     "py3exiv2==0.*,>=0.7.1,!=0.7.2,!=0.8.0,!=0.9.3",
diff --git a/tests/detectors/test_glasses_detector.py b/tests/detectors/test_glasses_detector.py
index 17e558522..f9d2a8f5c 100644
--- a/tests/detectors/test_glasses_detector.py
+++ b/tests/detectors/test_glasses_detector.py
@@ -9,8 +9,8 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 from os.path import abspath
+from unittest import mock
 
-import mock
 from preggy import expect
 from tornado.testing import gen_test
 
diff --git a/tests/detectors/test_profile_detector.py b/tests/detectors/test_profile_detector.py
index 94667674b..4253e798b 100644
--- a/tests/detectors/test_profile_detector.py
+++ b/tests/detectors/test_profile_detector.py
@@ -9,8 +9,8 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 from os.path import abspath
+from unittest import mock
 
-import mock
 from preggy import expect
 from tornado.testing import gen_test
 
diff --git a/tests/detectors/test_queued_detector.py b/tests/detectors/test_queued_detector.py
index 30ea17f3b..8ce883e08 100644
--- a/tests/detectors/test_queued_detector.py
+++ b/tests/detectors/test_queued_detector.py
@@ -9,8 +9,8 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 from json import loads
+from unittest import mock
 
-import mock
 from preggy import expect
 from redis import Redis
 from tornado.testing import gen_test
diff --git a/tests/engines/test_base_engine.py b/tests/engines/test_base_engine.py
index 44dfe0378..2eadd332a 100644
--- a/tests/engines/test_base_engine.py
+++ b/tests/engines/test_base_engine.py
@@ -12,10 +12,9 @@
 
 from os.path import abspath, dirname, join
 from struct import pack
-from unittest import TestCase
+from unittest import TestCase, mock
 from xml.etree.ElementTree import ParseError
 
-import mock
 from preggy import expect
 
 from thumbor.config import Config
diff --git a/tests/handlers/test_base_handler_respecting_orientation.py b/tests/handlers/test_base_handler_respecting_orientation.py
index 6a72be2d7..a123157be 100644
--- a/tests/handlers/test_base_handler_respecting_orientation.py
+++ b/tests/handlers/test_base_handler_respecting_orientation.py
@@ -13,11 +13,11 @@
 from preggy import expect
 from tornado.testing import gen_test
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import Context, ServerParameters
 from thumbor.engines.pil import Engine
 from thumbor.importer import Importer
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_auto_png_to_jpg.py b/tests/handlers/test_base_handler_with_auto_png_to_jpg.py
index f33143326..45d5c0199 100644
--- a/tests/handlers/test_base_handler_with_auto_png_to_jpg.py
+++ b/tests/handlers/test_base_handler_with_auto_png_to_jpg.py
@@ -8,15 +8,16 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
-from mock import patch
+from unittest.mock import patch
+
 from libthumbor import CryptoURL
 from preggy import expect
 from tornado.testing import gen_test
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import RequestParameters, ServerParameters
 from thumbor.importer import Importer
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_auto_webp.py b/tests/handlers/test_base_handler_with_auto_webp.py
index 93c0722b7..29ab8162c 100644
--- a/tests/handlers/test_base_handler_with_auto_webp.py
+++ b/tests/handlers/test_base_handler_with_auto_webp.py
@@ -9,17 +9,17 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 from shutil import which
+from unittest.mock import patch
 from urllib.parse import quote
 
+from libthumbor import CryptoURL
 from preggy import expect
 from tornado.testing import gen_test
-from mock import patch
-from libthumbor import CryptoURL
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import Context, RequestParameters, ServerParameters
 from thumbor.importer import Importer
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_cover.py b/tests/handlers/test_base_handler_with_cover.py
index b855ec403..7f3ec6cab 100644
--- a/tests/handlers/test_base_handler_with_cover.py
+++ b/tests/handlers/test_base_handler_with_cover.py
@@ -13,10 +13,10 @@
 from preggy import expect
 from tornado.testing import gen_test
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import Context, ServerParameters
 from thumbor.importer import Importer
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_different_storage_config.py b/tests/handlers/test_base_handler_with_different_storage_config.py
index 1764dbb0d..82b67f54b 100644
--- a/tests/handlers/test_base_handler_with_different_storage_config.py
+++ b/tests/handlers/test_base_handler_with_different_storage_config.py
@@ -14,13 +14,13 @@
 from preggy import expect
 from tornado.testing import gen_test
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import Context, ServerParameters
 from thumbor.engines.pil import Engine
 from thumbor.importer import Importer
 from thumbor.storages.file_storage import Storage as FileStorage
 from thumbor.storages.no_storage import Storage as NoStorage
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_engine_error.py b/tests/handlers/test_base_handler_with_engine_error.py
index ca0166db8..6afa5d8d6 100644
--- a/tests/handlers/test_base_handler_with_engine_error.py
+++ b/tests/handlers/test_base_handler_with_engine_error.py
@@ -8,16 +8,17 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
+from unittest.mock import patch
+
 import pytest
-from mock import patch
 from preggy import expect
 from tornado.testing import gen_test
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import Context, ServerParameters
 from thumbor.engines.pil import Engine
 from thumbor.importer import Importer
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_gifv.py b/tests/handlers/test_base_handler_with_gifv.py
index d398fb334..38a5891a7 100644
--- a/tests/handlers/test_base_handler_with_gifv.py
+++ b/tests/handlers/test_base_handler_with_gifv.py
@@ -14,10 +14,10 @@
 from preggy import expect
 from tornado.testing import gen_test
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import Context, ServerParameters
 from thumbor.importer import Importer
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_http_headers.py b/tests/handlers/test_base_handler_with_http_headers.py
index 07eb86bf9..9df4468cd 100644
--- a/tests/handlers/test_base_handler_with_http_headers.py
+++ b/tests/handlers/test_base_handler_with_http_headers.py
@@ -74,7 +74,7 @@ async def test_can_get_image_cors_header(self):
 
 class ImageOperationsWithCorsHeaderTestCase(BaseImagingTestCase):
     def get_context(self):
-        cfg = Config(SECURITY_KEY="ACME-SEC", ACCESS_CONTROL_ALLOW_ORIGIN_HEADER='*')
+        cfg = Config(SECURITY_KEY="ACME-SEC", ACCESS_CONTROL_ALLOW_ORIGIN_HEADER="*")
         cfg.LOADER = "thumbor.loaders.file_loader"
         cfg.FILE_LOADER_ROOT_PATH = self.loader_path
         cfg.ENABLE_ETAGS = False
@@ -93,7 +93,7 @@ async def test_can_get_image_with_cors_header(self):
 
         expect(response.code).to_equal(200)
         expect(response.headers).to_include("Access-Control-Allow-Origin")
-        expect(response.headers['Access-Control-Allow-Origin']).to_equal('*')
+        expect(response.headers["Access-Control-Allow-Origin"]).to_equal("*")
 
 
 class ImageOperationsWithLastModifiedTestCase(BaseImagingTestCase):
diff --git a/tests/handlers/test_base_handler_with_jpegtran.py b/tests/handlers/test_base_handler_with_jpegtran.py
index e6d84f73e..92ca95b85 100644
--- a/tests/handlers/test_base_handler_with_jpegtran.py
+++ b/tests/handlers/test_base_handler_with_jpegtran.py
@@ -17,14 +17,14 @@
 from preggy import expect
 from tornado.testing import gen_test
 
-from thumbor.config import Config
-from thumbor.context import Context, ServerParameters
-from thumbor.importer import Importer
 from tests.handlers.test_base_handler import (
-    BaseImagingTestCase,
-    JPEGTRAN_AVAILABLE,
     EXIFTOOL_AVAILABLE,
+    JPEGTRAN_AVAILABLE,
+    BaseImagingTestCase,
 )
+from thumbor.config import Config
+from thumbor.context import Context, ServerParameters
+from thumbor.importer import Importer
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_loader_error.py b/tests/handlers/test_base_handler_with_loader_error.py
index 4f5ef5247..865bbde2e 100644
--- a/tests/handlers/test_base_handler_with_loader_error.py
+++ b/tests/handlers/test_base_handler_with_loader_error.py
@@ -11,11 +11,11 @@
 from preggy import expect
 from tornado.testing import gen_test
 
+from tests.handlers.test_base_handler import BaseImagingTestCase
 from thumbor.config import Config
 from thumbor.context import Context, ServerParameters
 from thumbor.importer import Importer
 from thumbor.loaders import LoaderResult
-from tests.handlers.test_base_handler import BaseImagingTestCase
 
 # pylint: disable=broad-except,abstract-method,attribute-defined-outside-init,line-too-long,too-many-public-methods
 # pylint: disable=too-many-lines
diff --git a/tests/handlers/test_base_handler_with_native_gif_handling.py b/tests/handlers/test_base_handler_with_native_gif_handling.py
index cdcec4558..ee3085885 100644
--- a/tests/handlers/test_base_handler_with_native_gif_handling.py
+++ b/tests/handlers/test_base_handler_with_native_gif_handling.py
@@ -10,8 +10,8 @@
 
 import os
 from os.path import dirname
+from unittest.mock import Mock
 
-from mock import Mock
 from preggy import expect
 from tornado.testing import gen_test
 
diff --git a/tests/handlers/test_base_handler_with_result_storage.py b/tests/handlers/test_base_handler_with_result_storage.py
index 05a2a9368..8be991afe 100644
--- a/tests/handlers/test_base_handler_with_result_storage.py
+++ b/tests/handlers/test_base_handler_with_result_storage.py
@@ -11,8 +11,8 @@
 import os
 from os.path import dirname
 from shutil import which
+from unittest.mock import Mock, patch
 
-from mock import Mock, patch
 from preggy import expect
 from tornado.testing import gen_test
 
diff --git a/tests/handlers/test_fetch_result.py b/tests/handlers/test_fetch_result.py
index 9ffdd5875..f3680ecd7 100644
--- a/tests/handlers/test_fetch_result.py
+++ b/tests/handlers/test_fetch_result.py
@@ -8,7 +8,8 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
-from mock import Mock
+from unittest.mock import Mock
+
 from preggy import expect
 
 from tests.base import TestCase
diff --git a/tests/loaders/test_file_loader_http_fallback.py b/tests/loaders/test_file_loader_http_fallback.py
index 78eb961b3..b7ee52876 100644
--- a/tests/loaders/test_file_loader_http_fallback.py
+++ b/tests/loaders/test_file_loader_http_fallback.py
@@ -9,8 +9,8 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 from os.path import abspath, dirname, join
+from unittest.mock import patch
 
-from mock import patch
 from preggy import expect
 from tornado.testing import gen_test
 
diff --git a/tests/metrics/test_default_metrics.py b/tests/metrics/test_default_metrics.py
index 5bccbc4be..1942137a8 100644
--- a/tests/metrics/test_default_metrics.py
+++ b/tests/metrics/test_default_metrics.py
@@ -8,13 +8,13 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
-import mock
+from unittest import mock
+
 from preggy import expect
 
 import thumbor.metrics
-from thumbor.importer import Importer
-
 from tests.base import TestCase
+from thumbor.importer import Importer
 
 
 class DefaultMetricsTestCase(TestCase):
diff --git a/tests/metrics/test_logger_metrics.py b/tests/metrics/test_logger_metrics.py
index 147f82d4a..ae9d8f43d 100644
--- a/tests/metrics/test_logger_metrics.py
+++ b/tests/metrics/test_logger_metrics.py
@@ -10,12 +10,11 @@
 
 from preggy import expect
 
-from thumbor.context import Context
-from thumbor.importer import Importer
-from thumbor.config import Config
 import thumbor.metrics
-
 from tests.base import TestCase
+from thumbor.config import Config
+from thumbor.context import Context
+from thumbor.importer import Importer
 
 
 class LoggerMetricsTestCase(TestCase):
diff --git a/tests/metrics/test_statsd_metrics.py b/tests/metrics/test_statsd_metrics.py
index 904111acb..1d13ad11c 100644
--- a/tests/metrics/test_statsd_metrics.py
+++ b/tests/metrics/test_statsd_metrics.py
@@ -10,12 +10,11 @@
 
 from preggy import expect
 
-from thumbor.context import Context
-from thumbor.importer import Importer
-from thumbor.config import Config
 import thumbor.metrics
-
 from tests.base import TestCase
+from thumbor.config import Config
+from thumbor.context import Context
+from thumbor.importer import Importer
 
 
 class StatsdMetricsTestCase(TestCase):
diff --git a/tests/optimizers/test_gifv.py b/tests/optimizers/test_gifv.py
index 4dbce64ab..f78ca5999 100644
--- a/tests/optimizers/test_gifv.py
+++ b/tests/optimizers/test_gifv.py
@@ -9,9 +9,7 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 from shutil import which
-from unittest import TestCase
-
-import mock
+from unittest import TestCase, mock
 
 from thumbor.config import Config
 from thumbor.context import Context, RequestParameters
diff --git a/tests/optimizers/test_jpegtran.py b/tests/optimizers/test_jpegtran.py
index 731a14389..82908b73a 100644
--- a/tests/optimizers/test_jpegtran.py
+++ b/tests/optimizers/test_jpegtran.py
@@ -8,9 +8,7 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
-from unittest import TestCase
-
-import mock
+from unittest import TestCase, mock
 
 from thumbor.config import Config
 from thumbor.context import Context, RequestParameters
diff --git a/tests/result_storages/test_file_storage.py b/tests/result_storages/test_file_storage.py
index 97b7e31b5..48f4a6490 100644
--- a/tests/result_storages/test_file_storage.py
+++ b/tests/result_storages/test_file_storage.py
@@ -11,8 +11,8 @@
 import tempfile
 from datetime import datetime
 from os.path import abspath, dirname, join
+from unittest import mock
 
-import mock
 from preggy import expect
 from tornado.testing import gen_test
 
diff --git a/tests/storages/test_file_storage.py b/tests/storages/test_file_storage.py
index d9cf92e24..6d38832f1 100644
--- a/tests/storages/test_file_storage.py
+++ b/tests/storages/test_file_storage.py
@@ -12,8 +12,8 @@
 from datetime import datetime
 from os.path import dirname, exists, join
 from tempfile import mkdtemp
+from unittest import mock
 
-import mock
 from preggy import expect
 from tornado.testing import gen_test
 
diff --git a/tests/test_config.py b/tests/test_config.py
index 6c3487908..4f2595ac8 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -9,12 +9,11 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 from os.path import expanduser
-from unittest import TestCase
-import mock
+from unittest import TestCase, mock
 
 from preggy import expect
 
-from thumbor.config import generate_config, format_value, Config
+from thumbor.config import Config, format_value, generate_config
 
 
 class ConfigTestCase(TestCase):
diff --git a/tests/test_context.py b/tests/test_context.py
index 3d21a715a..3406b78b5 100644
--- a/tests/test_context.py
+++ b/tests/test_context.py
@@ -8,9 +8,8 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
-from unittest import TestCase
+from unittest import TestCase, mock
 
-import mock
 from preggy import expect
 
 from thumbor.config import Config
diff --git a/tests/test_point.py b/tests/test_point.py
index 05e3494a1..bdd6a7917 100644
--- a/tests/test_point.py
+++ b/tests/test_point.py
@@ -10,9 +10,8 @@
 
 from preggy import expect
 
-from thumbor.point import FocalPoint
-
 from tests.base import TestCase
+from thumbor.point import FocalPoint
 
 
 class FocalPointTestCase(TestCase):
diff --git a/tests/test_server.py b/tests/test_server.py
index caaac20c3..c176d4887 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -8,9 +8,8 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
-from unittest import TestCase
+from unittest import TestCase, mock
 
-import mock
 from preggy import expect
 
 import thumbor.server
diff --git a/tests/test_signal_handler.py b/tests/test_signal_handler.py
index 552aecc27..5adb1b213 100644
--- a/tests/test_signal_handler.py
+++ b/tests/test_signal_handler.py
@@ -9,9 +9,7 @@
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
 import signal
-from unittest import TestCase
-
-import mock
+from unittest import TestCase, mock
 
 from thumbor.signal_handler import setup_signal_handler, signal_handler
 
diff --git a/tests/test_threadpool.py b/tests/test_threadpool.py
index 89bd3f0a3..9b5c2c58b 100644
--- a/tests/test_threadpool.py
+++ b/tests/test_threadpool.py
@@ -11,8 +11,8 @@
 # pylint: disable=protected-access
 
 from time import sleep
+from unittest import mock
 
-import mock
 import pytest
 from preggy import expect
 
diff --git a/tests/test_url_composer.py b/tests/test_url_composer.py
index bb5d9fb99..0edd22c1b 100644
--- a/tests/test_url_composer.py
+++ b/tests/test_url_composer.py
@@ -11,9 +11,8 @@
 import optparse
 import sys
 from io import StringIO
-from unittest import TestCase
+from unittest import TestCase, mock
 
-import mock
 from preggy import expect
 
 import thumbor.url_composer as composer
diff --git a/tests/test_utils.py b/tests/test_utils.py
index ba1c87ef4..0a692d618 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -10,9 +10,8 @@
 
 import logging
 from shutil import which
-from unittest import TestCase
+from unittest import TestCase, mock
 
-from mock import patch
 from preggy import expect
 
 from thumbor.utils import CONTENT_TYPE, EXTENSION, deprecated, logger
@@ -57,7 +56,7 @@ def test_deprecated_logs_msg():
         def test_func():
             pass
 
-        with patch.object(logger, "warning") as mock_warn:
+        with mock.patch.object(logger, "warning") as mock_warn:
             test_func()
             mock_warn.assert_called_once_with(
                 "Deprecated function %s%s", "test_func", "func2"