diff --git a/zuul.d/ironic-jobs.yaml b/zuul.d/ironic-jobs.yaml
index a8c5c874a0..e9cc8bdbe7 100644
--- a/zuul.d/ironic-jobs.yaml
+++ b/zuul.d/ironic-jobs.yaml
@@ -101,7 +101,7 @@
       - ^tox.ini$
     vars:
       tempest_test_regex: ironic_standalone
-      tempest_concurrency: 3
+      tempest_concurrency: 2
       devstack_localrc:
         FORCE_CONFIG_DRIVE: False
         IRONIC_AUTOMATED_CLEAN_ENABLED: False