diff --git a/tox.ini b/tox.ini
index 9d81dc1d869..4000908ba8c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -42,7 +42,7 @@ deps =
 # the concurrency=<n> option.
 # call ie: 'tox -epy27 -- --concurrency=4'
 commands =
-  stestr run {posargs}
+  stestr run --random {posargs}
   stestr slowest
 
 allowlist_externals =