diff --git a/docs/requirements.txt b/docs/requirements.txt
index 7d2b038..2de526f 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,5 +1,7 @@
 pydata-sphinx-theme
-sphinx>=4
+# Sphix 6.0.0 breaks pydata-sphinx-theme
+# See pydata/pydata-sphinx-theme#1094
+sphinx<6
 sphinx_copybutton
 sphinx-autobuild
 sphinxext-opengraph