diff --git a/pyproject.toml b/pyproject.toml
index e95f93a..44171e0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -40,7 +40,7 @@ jinja = ["Jinja2"]
 compression = ["brotli"]
 all = ["Logbook[execnet,sqlalchemy,redis,zmq,jinja,compression,nteventlog]"]
 nteventlog = ["pywin32; platform_system == 'Windows'"]
-docs = ["Sphinx"]
+docs = ["Sphinx>=5"]
 
 [tool.setuptools.dynamic]
 version = { attr = "logbook.__version__" }