diff --git a/tox.ini b/tox.ini
index 83b5cec47a..430e318b10 100644
--- a/tox.ini
+++ b/tox.ini
@@ -41,6 +41,8 @@ commands =
   bash -c "find playbooks -type f -regex '.*.ya?ml' -exec \
     ansible-playbook --syntax-check -i {toxinidir}/tests/inventory \
     -e @tests/vars.yaml \{\} + > /dev/null"
+  # Make sure site-variables at least parses
+  python -c 'import yaml ; yaml.load(open("zuul/site-variables.yaml", "r"))'
 
 [testenv:gerrit]
 deps = PyYAML