diff --git a/.readthedocs.yml b/.readthedocs.yml
index 38e8cd6815..c8d22caea4 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -1,6 +1,11 @@
 # Required
 version: 2
 
+build:
+  os: ubuntu-20.04
+  tools:
+    python: "3.8"
+
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
   configuration: docs/source/conf.py