diff --git a/tox.ini b/tox.ini
index 8a0da92c2..0670b7ee2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -41,7 +41,6 @@ commands =
 # https://github.com/certbot/certbot/issues/7745.
 recreate = true
 setenv =
-    PYTEST_ADDOPTS = {env:PYTEST_ADDOPTS:--numprocesses auto}
     PYTHONHASHSEED = 0
 
 [testenv:oldest]