diff --git a/tox.ini b/tox.ini
index c8f23c7..10a99ba 100644
--- a/tox.ini
+++ b/tox.ini
@@ -39,7 +39,7 @@ deps = sphinx>=7.2.3
        sphinx_rtd_theme
        pycups
 commands = sphinx-build -W -b html -d {envtmpdir}/doctrees .  {envtmpdir}/html
-           sphinx-build -b spelling -d {envtmpdir}/doctrees .  {envtmpdir}/spelling
+           sphinx-build -W -b spelling -d {envtmpdir}/doctrees .  {envtmpdir}/spelling
 
 [testenv:flake8]
 basepython = python