A semiconductor memory device includes a first semiconductor chip including a first pad group configured to input/output first data and a second pad group configured to input/output second data; and a second semiconductor chip in a stack with the first semiconductor chip and configured to be electrically connected to the first semiconductor chip by at least one chip through via, wherein the second semiconductor chip includes a first unit bank group including at least one first upper bank group and at least one first lower bank group, a second unit bank group including at least one second upper bank group and at least one second lower bank group, and a data path selector configured to electrically connect one among the first and second upper bank groups and the first and second lower bank groups with the chip through via.