diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index a28678b8f..b7303cf6b 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -8,5 +8,5 @@ version: 2
 # Set the version of Python and other tools you might need
 build:
   os: ubuntu-20.04
-  tools
+  tools:
     python: "3.9"