diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 3018713..df413fa 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -38,7 +38,7 @@ build:
       # Suppress spell warnings because readthdocs uses a different dictionry.
       - xrst
          --page_source
-         --html_theme furo
+         --html_theme sphinx_book_theme
          --group_list default user
          --index_page_name user-guide
          --suppress_spell_warnings