diff --git a/setup.cfg b/setup.cfg
index 36af53e..4636d14 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -27,7 +27,7 @@ test =
     pytest
     pytest-cov
 docs =
-    sphinx
+    sphinx<7
     numpydoc
     sphinx-astropy
     aplpy