diff --git a/tox.ini b/tox.ini
index fd328a282d..03143eb5b2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -140,6 +140,7 @@ import_exceptions =
 local-check-factory = ceilometer.hacking.checks.factory
 
 [testenv:api-ref]
+whitelist_externals = rm
 commands =
   rm -rf api-ref/build
   sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html