diff --git a/setup.py b/setup.py
index bddc76b3..329438ef 100644
--- a/setup.py
+++ b/setup.py
@@ -51,10 +51,9 @@ tests_require = [
     "pytest-mock>=3,<4",
     "pytest-asyncio>=0.16,<2",
     "coveralls>=3.3,<5",
-    "types-python-dateutil>=2.8.1,<3",
 ]
 
-dev_requires = ["ruff==0.5.0"] + tests_require
+dev_requires = ["ruff==0.5.0", "types-python-dateutil>=2.8.1,<3"] + tests_require
 
 setup(
     name="graphene",
diff --git a/tox.ini b/tox.ini
index 52a7e552..327bdb37 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,7 +20,7 @@ commands =
 [testenv:mypy]
 basepython = python3.10
 deps =
-    mypy>=1.10,<2
+    mypy>=1.10,<2, .[dev]
 commands =
     mypy graphene