diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index c8eb2db..7bcfac9 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -4,6 +4,9 @@ build:
   os: "ubuntu-20.04"
   tools:
     python: "3.8"
+  jobs:
+    post_create_environment:
+      - python -m pip install sphinx_rtd_theme
 
 sphinx:
   fail_on_warning: true