diff --git a/setup.py b/setup.py
index 981dac808..ec7ad890c 100644
--- a/setup.py
+++ b/setup.py
@@ -45,6 +45,7 @@ def get_setup_version(reponame):
         'pre-commit',
         'matplotlib >=3.4',  # Ubuntu + Python 3.9 installs old version matplotlib (3.3.2)
         'pytest-github-actions-annotate-failures',
+        'pytest-xdist',
     ],
     'doc': [
         'nbsite >=0.8.2',
diff --git a/tox.ini b/tox.ini
index d5d9281a7..6887ff96b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,7 +20,7 @@ commands = flake8
 [_unit]
 description = Run unit tests
 deps = .[tests]
-commands = pytest lumen --cov=./lumen --cov-append
+commands = pytest lumen --cov=./lumen --cov-append -n auto --dist loadgroup
 
 [_all]
 description = Run all tests (but only including default examples)