diff --git a/tox.ini b/tox.ini
index b32e01086c03..5df99a336639 100644
--- a/tox.ini
+++ b/tox.ini
@@ -76,7 +76,7 @@ deps =
   -r{toxinidir}/requirements-dev.txt
   qiskit-aer
 commands =
-  sphinx-build -W -T --keep-going -b html docs/ docs/_build/html {posargs}
+  sphinx-build -W -j auto -T --keep-going -b html docs/ docs/_build/html {posargs}
 
 [pycodestyle]
 max-line-length = 105