diff --git a/doc/joined-requirements.txt b/doc/joined-requirements.txt
new file mode 100644
index 0000000..3b4c245
--- /dev/null
+++ b/doc/joined-requirements.txt
@@ -0,0 +1,4 @@
+# This file is needed because readthedocs people refuse to support several
+# requirements files at once, and using autodoc requires installing both.
+-r requirements.txt
+-r ../requirements.txt
diff --git a/tox.ini b/tox.ini
index 2805b51..977df70 100644
--- a/tox.ini
+++ b/tox.ini
@@ -31,8 +31,7 @@ commands =
 [testenv:docs]
 deps =
     -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
-    -r{toxinidir}/requirements.txt
-    -r{toxinidir}/doc/requirements.txt
+    -r{toxinidir}/doc/joined-requirements.txt
 commands =
   sphinx-build -a -E -W -b html doc/source doc/build/html