diff --git a/setup.cfg b/setup.cfg
index f6276cb173..75647e6623 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -69,7 +69,7 @@ where = lib
 
 [options.extras_require]
 docs =
-    sphinx
+    sphinx<5
     sphinx-copybutton
     sphinx-gallery>=0.11.0
     sphinx_rtd_theme