A battery pack includes a first battery module, the first battery module including unit batteries, a first plate, and a second plate, and a second battery module, the second battery module including unit batteries, a first plate, and a second plate. The first battery module may be stacked on the second battery module, the second plate of the first battery module may be between the first battery module and the second battery module, and the second plate of the first battery module may support the unit batteries of the first battery module and contact the first plate of the second battery module.