diff --git a/pyproject.toml b/pyproject.toml
index fb511ade..48b346d7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -94,7 +94,7 @@ test = [
     "pytest>=7.1.3,<9.0.0",
     "pytest-cov>=4.1.0,<5.0.0",
     "pytest-asyncio>=0.20.0",
-    "mypy==1.8.0",
+    "mypy==1.9.0",
     "flake8>=5.0.4",
     "aiofiles>=0.8.0,<24",
     "a2wsgi>=1.9.0,<2",