A battery pack includes a battery module including a plurality of battery cells that are electrically connected, a first case accommodating the battery module, and a second case opposite to the first case so as to be coupled to the first case. The first or second case includes an extending portion, the extending portion being provided to extend in a first direction, the first direction being a direction in which the first and second cases are coupled to each other, so as to shield a portion at which the first and second cases are coupled to each other.