A vertical memory device includes a substrate including a cell array region and a connection region adjacent to the cell array region, a plurality of gate electrode layers stacked on the cell array region and the connection region of the substrate, a channel structure on the cell array region and extending in a direction perpendicular to an upper surface of the substrate while penetrating through the plurality of gate electrode layers, a dummy channel structure on the connection region and extending in the direction perpendicular to the upper surface of the substrate while penetrating through at least a portion of the plurality of gate electrode layers, and a support insulating layer between a portion of the plurality of gate electrode layers and the dummy channel structure. The plurality of gate electrode form a stepped structure on the connection region.