diff --git a/tox.ini b/tox.ini
index 8194feb..1f71f4b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,4 +23,4 @@ passenv = *
 deps=
     -rdoc-requirements.txt
 commands=
-    python setup.py build_sphinx
+    python setup.py build_sphinx --builder=html