Wash your hands well with soap and warm water for at least 20 seconds.
Coat 9 x 13 baking dish with vegetable oil spray.
Wash squash, zucchini, and tomatoes and cut into about 1/4-inch slices. Layer the squash, zucchini, and tomato slices so that they are alternating and overlapping.
Drizzle oil over squash, zucchini and tomato slices.
Season squash, zucchini and tomato slices with Italian seasoning, salt, and pepper.
Sprinkle cheese over dish and bake in the oven for 30 minutes.