Disclosed herein are polymer blends comprising at least one ethylene/.alpha.-olefin interpolymer and two different polyolefins which can be homopolymers. The ethylene/.alpha.-olefin interpolymers are block copolymers comprising at least a hard block and at least a soft block. In some embodiments, the ethylene/.alpha.-olefin interpolymer can function as a compatibilizer between the two polyolefins which may not be otherwise compatible. Methods of making the polymer blends and molded articles made from the polymer blends are also described.