diff --git a/HISTORY.rst b/HISTORY.rst
index d303acfd..2883c614 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -4,6 +4,7 @@ History
 
 X.Y.Z (YYYY-MM-DD)
 ------------------
+* Pin flake8 to >= 4.0.0 and < 5.0.0 (:pr:`272`)
 * Document Fused RIME (:pr:`270`)
 * Add Multiton, LazyProxy and LazyProxyMultiton patterns (:pr:`269`)
 
diff --git a/setup.py b/setup.py
index 1fc2cd2e..74a387ba 100644
--- a/setup.py
+++ b/setup.py
@@ -31,10 +31,11 @@
     "astropy": ["astropy >= 4.0"],
     "python-casacore": ["python-casacore >= 3.4.0"],
     "ducc0": ["ducc0 >= 0.9.0"],
-    "testing": ["pytest", "flaky", "pytest-flake8 >= 1.0.6"],
+    "testing": ["pytest", "flaky", "pytest-flake8 >= 1.0.6", "flake8 >= 4.0.0, < 5.0.0"],
 }
 
 with open(str(Path("africanus", "install", "extras_require.py")), "w") as f:
+    f.write("# flake8: noqa")
     f.write("extras_require = {\n")
     for k, v in extras_require.items():
         f.write("   '%s': %s,\n" % (k, v))