diff --git a/docs/requirements_base.txt b/docs/requirements_base.txt
index baebc41b5e1c..9314ee0deb35 100644
--- a/docs/requirements_base.txt
+++ b/docs/requirements_base.txt
@@ -1,2 +1,2 @@
-sphinx
+sphinx < 4
 sphinx_rtd_theme >= 0.5