diff --git a/readthedocs.yml b/readthedocs.yml
index f85d2493..4fae81d6 100644
--- a/readthedocs.yml
+++ b/readthedocs.yml
@@ -2,4 +2,5 @@ name: repo2docker
 type: sphinx
 python:
   version: 3
+  setup_py_install: true
 requirements_file: docs/doc-requirements.txt