diff --git a/requirements.txt b/requirements.txt
index ca66471..508d04f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 #
-sphinx~=8.0
+sphinx~=9.1
 sphinx-rtd-theme~=3.0
 sphinxcontrib-spelling~=8.0
 sphinx-gallery~=0.20