A vertical memory device includes a substrate with a cell region, a through via region on opposite sides of the cell region, and a mold region surrounding the cell and through via regions, gate electrodes spaced apart from each other along a first direction vertical to an upper surface of the substrate, and extending in a second direction parallel to the upper surface of the substrate, a channel extending in the first direction on the cell region, and extending through at least a portion of the stacked gate electrodes, and a first mold including first and second layers alternately and repeatedly stacked along the first direction on the mold region, the first and second layers including different insulation materials from each other, and each of the second layers of the first mold being at the same height as and contact a corresponding one of the gate electrodes.