diff --git a/tox.ini b/tox.ini
index 832b97298..87d8141a3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -156,7 +156,7 @@ markers =
 
 [flake8]
 max-line-length = 120
-ignore = E203,W503
+extend-ignore = E203
 
 [isort]
 ; This config mimics what reorder-python-imports does.