diff --git a/requirements.txt b/requirements.txt
index dce7d7a..9e9dd8d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ myst-parser==5.0.0
 rcssmin==1.2.2
 rjsmin==1.2.5
 shibuya==2026.1.9
-sphinx==8.2.3
+sphinx==9.1.0
 sphinx-contributors==0.2.7
 sphinx-copybutton==0.5.2
 sphinx-design==0.7.0