diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 9e5ba778..ef0dba06 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -9,6 +9,9 @@ build:
   os: ubuntu-22.04
   tools:
     python: "mambaforge-22.9"
+  jobs:
+    post_create_environment:
+      - python -m pip install sphinx_rtd_theme
 
 conda:
   environment: conda_env.yml