A stacked semiconductor device may have a plurality of chips stacked in three-dimension. The stacked semiconductor device may include a first semiconductor chip and at least one second semiconductor chip. The first semiconductor chip may include a plurality of first through silicon vias (TSVs). The at least one second semiconductor chip may include a plurality of second TSVs. The at least one second semiconductor chip may be stacked above the first semiconductor chip and may be thinner than the first semiconductor chip. Therefore, the stacked semiconductor device may have an improved reliability.