diff --git a/tox.ini b/tox.ini
index bc44df987..75a00961e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -209,4 +209,4 @@ deps =
     -r{toxinidir}/misc/requirements/requirements-pyqt.txt
     -r{toxinidir}/misc/requirements/requirements-sphinx.txt
 commands =
-    {envpython} -m sphinx -jauto -W --color {posargs} doc/extapi/ doc/extapi/_build/
+    {envpython} -m sphinx -jauto -W --color {posargs} {toxinidir}/doc/extapi/ {toxinidir}/doc/extapi/_build/