diff --git a/pytest.ini b/pytest.ini
index 8f009045c..654b368f2 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -2,7 +2,6 @@
 # settings we want to also change there must be added to the release script
 # directly.
 [pytest]
-addopts = --numprocesses auto --pyargs
 # In general, all warnings are treated as errors. Here are the exceptions:
 #   1- decodestring: https://github.com/rthalley/dnspython/issues/338
 #   2- ignore our own TLS-SNI-01 warning
diff --git a/tox.ini b/tox.ini
index 363f06bf2..76de2ea36 100644
--- a/tox.ini
+++ b/tox.ini
@@ -70,6 +70,7 @@ commands =
     {[base]install_and_test} {[base]all_packages}
     python tests/lock_test.py
 setenv =
+    PYTEST_ADDOPTS = {env:PYTEST_ADDOPTS:--numprocesses auto --pyargs}
     PYTHONHASHSEED = 0
 
 [testenv:py27-oldest]