A three-dimensional semiconductor memory device includes a peripheral logic structure including a plurality of peripheral logic circuits disposed on a semiconductor substrate, a horizontal semiconductor layer disposed on the peripheral logic structure, an electrode structure including a plurality of electrodes and insulating layers vertically and alternately stacked on the horizontal semiconductor layer, and a through-interconnection structure penetrating the electrode structure and the horizontal semiconductor layer and including a through-plug connected to the peripheral logic structure. A sidewall of a first insulating layer of the insulating layers is spaced apart from the through-plug by a first distance. A sidewall of a first electrode of the electrodes is spaced apart from the through-plug by a second distance greater than the first distance.