Do I need a box spring with this mattress?

You do not need a traditional spring box, but this 16-inch luxury hybrid does need firm, even support underneath: a solid foundation, a platform bed, an adjustable base, or closely spaced slats. A matching foundation is commonly paired with it and one owner noted the combined height made getting in and out easier. In Canada the mattress and foundation are sold and trialled separately, so plan your base before delivery.