Preheat oven to 350°. Grease 9x13 baking dish
Place a layer of frozen ravioli along bottom of dish
Add spoonfuls of spaghetti sauce on top
Sprinkle sauce covered ravioli generously with mozzarella cheese
Repeat this process until the dish is full
Add a layer of frozen meatballs to the top and sprinkle with grated parm
Cover with aluminum foil and bake until hot and bubbly - 45 minutes to an hour.