diff --git a/pyproject.toml b/pyproject.toml
index 9b7fbaf5..c89dfa60 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ dependencies = [
 
 [project.optional-dependencies]
 docs = [
-    "sphinx==8.2.3",
+    "sphinx==9.1.0",
     "sphinx_rtd_theme==3.0.2",
 ]
 test = [