Heat oven to 350ºF. Spray 13x9-inch (3-quart) glass baking dish with nonstick cooking spray. In sprayed dish, combine pasta sauce and soup; mix well.
Add frozen ravioli, and bell pepper and onion stir-fry; stir to coat. Cover with foil.
Bake 1 hour. Uncover baking dish; sprinkle with cheese. Bake uncovered 5 to 10 minutes longer or until casserole is bubbly and cheese is melted.