diff --git a/tox.ini b/tox.ini
index fdec36b..7a9860b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,3 +23,14 @@ commands =
     coverage combine
     coverage html
     coverage report -m --fail-under 99
+
+[testenv:docs]
+# basepython not specified; we want to be sure it's something available
+# on the current system.
+deps =
+    sphinx
+    sphinxcontrib-programoutput
+commands =
+    make -C doc html
+whitelist_externals =
+    make