diff --git a/setup.cfg b/setup.cfg
index c2428b09..e7419edb 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -40,6 +40,7 @@ docs =
     rst.linker>=1.9
     sphinx
 testing =
+    flake8<4  # workaround https://github.com/tholo/pytest-flake8/issues/81
     pytest>=6
     pytest-black>=0.3.7
     pytest-checkdocs>=2.4