diff --git a/tox.ini b/tox.ini
index 05fa326..678bbd0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -88,7 +88,7 @@
 # See the testrepository bug: https://bugs.launchpad.net/testrepository/+bug/1208610
 commands =
     find . -type f -name "*.pyc" -delete
-    tempest run --regex '(?!.*\[.*\bslow\b.*\])(^tempest\.(api|scenario))' {posargs}
+    tempest run --serial --regex '(?!.*\[.*\bslow\b.*\])(^tempest\.(api|scenario))' {posargs}
 
 [testenv:smoke]
 envdir = .tox/tempest