diff --git a/pyproject.toml b/pyproject.toml
index 4ff5b3e..55fc184 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -49,7 +49,7 @@ dependencies = [
   "mdformat-gfm==1.0.0",
   "mdformat-black==0.1.1",
   "numpy==2.3.4",
-  "sphinx==8.2.3",
+  "sphinx==9.0.0",
   "sphinx-rtd-theme==3.0.2",
 ]