diff --git a/docs/requirements.txt b/docs/requirements.txt
index 487a7d7..630e760 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,5 +1,5 @@
 mock
-# Remove sphinx from requirements b/c it lead to issues
-# on rtd and it's a dependency of the rtd theme anyway.
-# sphinx>=1.6.4,<2
+sphinx==4.3.0
 sphinxcontrib.bibtex>=2.0
+sphinx_rtd_theme==1.0
+