Yes, you can freeze tuna noodle casserole to be enjoyed at a later date. You can leave it in the same dish you baked it in if you have an airtight lid for it. Or you can portion out the casserole. If it is just you and your partner, divide the casserole into individual serving-sized portions and put them in freezer-safe containers. Then, you can thaw and reheat only what you need. Tuna casserole can be kept in the freezer for about 2 or 3 months, but try to use it up before that for the best quality and texture of the casserole. When you are ready to use the leftovers, take the tuna casserole out of the freezer the night before and let it thaw in the refrigerator. Reheat it in the oven until it is heated through.