The present disclosure relates to a casing for a battery pack and a battery pack. The casing has a receiving space and an opening in communication with the receiving space, the receiving space is formed by a wall portion of the casing, and the wall portion is formed from two or more stacked base plates, between which a plurality of cavities are formed. By forming a plurality of cavities in the wall portion, the casing for a battery pack provided by the present disclosure not only can improve the bearing capacity and the impact resistance of the casing, but also can achieve a thermal management of the battery assembly by filling the plurality of cavities with a phase change material or cooling liquid, which can further improve the mechanical property of the casing with a relatively light weight and relatively high reliability.