diff --git a/setup.cfg b/setup.cfg
index 48ae7a69d5..18ae634e14 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -53,7 +53,8 @@ testing =
 		# workaround for jaraco/skeleton#22
 		python_implementation != "PyPy"
 	pytest-enabler >= 1.3
-	pytest-ruff
+	# workaround for pypa/setuptools#3921
+	pytest-ruff; sys_platform != "cygwin"
 
 	# local
 	flake8-2020