diff --git a/tox.ini b/tox.ini
index 852318a..7f7bd26 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,7 +26,7 @@ commands = black --check --diff --fast .
 
 [testenv:flake8]
 deps =
-    flake8
+    flake8<6.0.0  # TODO remove pinned version once https://github.com/zheller/flake8-quotes/pull/111 is merged.
     flake8-black
     flake8-docstrings
     flake8-quotes