diff --git a/docs/requirements.txt b/docs/requirements.txt
index 70739640a..de42439d9 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,5 +1,5 @@
 sphinx==4.*
 myst-parser
-sphinx_rtd_theme
+sphinx_rtd_theme==1.0.*
 sphinxcontrib-spelling==7.3.0
 sphinx-autodoc-typehints