diff --git a/CHANGES.rst b/CHANGES.rst
index 8afb72189..28e3fe5e2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -42,6 +42,7 @@ fixes:
 - docs: add readthedocs yaml config (#1661)
 - fix: broken integration tests (#1668)
 - style: replace format() with f-strings (#1667)
+- migrate from external mock package to stdlib unittest.mock (#1673)
 
 
 v6.1.9 (2022-06-11)
diff --git a/tests/cascade_dependencies_test.py b/tests/cascade_dependencies_test.py
index 357df721c..bbe920cd9 100644
--- a/tests/cascade_dependencies_test.py
+++ b/tests/cascade_dependencies_test.py
@@ -1,7 +1,7 @@
 import os
 import pathlib
 
-import mock
+from unittest import mock
 import pytest
 
 extra_plugin_dir = os.path.join(
diff --git a/tests/commands_test.py b/tests/commands_test.py
index 8d33df577..5eaaa8dd1 100644
--- a/tests/commands_test.py
+++ b/tests/commands_test.py
@@ -9,7 +9,7 @@
 from tempfile import mkdtemp
 
 import pytest
-from mock import MagicMock
+from unittest.mock import MagicMock
 
 extra_plugin_dir = path.join(path.dirname(path.realpath(__file__)), "dummy_plugin")
 
diff --git a/tests/requirements.txt b/tests/requirements.txt
deleted file mode 100644
index 932a8957f..000000000
--- a/tests/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-mock
diff --git a/tox.ini b/tox.ini
index 17efb4066..9a4841e59 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,6 @@ skip_missing_interpreters = True
 
 [testenv]
 deps =
-    mock
     pytest
     slackclient>=1.0.5,<2.0