diff --git a/tox.ini b/tox.ini
index 04a0e5bf7d1..eb08d5a203d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,3 +18,10 @@ commands = pytest --cov-report html --cov plugins {posargs:tests/}
 deps = coverage
 skip_install = true
 commands = coverage erase
+
+[testenv:complexity-report]
+deps =
+  # See: https://github.com/lordmauve/flake8-html/issues/30
+  flake8>=3.3.0,<5.0.0'
+  flake8-html
+commands = -flake8 --select C90 --max-complexity 10 --format=html --htmldir={posargs} plugins