A semiconductor device includes a cell area including a plurality of word lines stacked on a substrate, at least one ground select line between the plurality of word lines and substrate, and a plurality of channel structures passing through the plurality of word lines and the at least one ground select line, and a peripheral circuit area including peripheral circuits controlling the cell area. The peripheral circuits input a first ground select bias voltage to the at least one ground select line during a first program time to a program word line selected from among the plurality of word lines, and input a second ground select bias voltage having a magnitude different from the first ground select bias voltage to the at least one ground select line during a second program time, the second program voltage different from the first program voltage.