diff --git a/docs/api_docs/python/requirements.txt b/docs/api_docs/python/requirements.txt
index 4f8fa23fe..11244dc86 100644
--- a/docs/api_docs/python/requirements.txt
+++ b/docs/api_docs/python/requirements.txt
@@ -2,5 +2,6 @@ sphinx
 recommonmark
 sphinx_markdown_tables
 sphinx_rtd_theme
+sphinx_book_theme
 furo
 myst_parser