diff --git a/setup.cfg b/setup.cfg
index 6f34959..437ab23 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -59,7 +59,7 @@ dev =
     types-tqdm
 docs =
     pydata-sphinx-theme
-    sphinx
+    sphinx<6.0.0
     sphinx-autoapi
     sphinx-click