diff --git a/pyproject.toml b/pyproject.toml
index beb5b9bee..6d9c86ef3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -60,7 +60,7 @@ lint = [
     "ruff",
 ]
 docs = [
-    "sphinx<8.0.0",
+    "sphinx<9.0.0",
     "sphinx-rtd-theme",
     "sphinxcontrib-napoleon",
     "nbsphinx",