A vertical memory device includes a plurality of gate lines, at least one etch-stop layer, channels, and contacts. The gate lines are stacked and spaced apart from each other along a first direction with respect to a surface of substrate. Each of the gate lines includes step portion protruding in a second direction. The at least one etch-stop layer covers the step portion of at least one of the gate lines and includes conductive material. The channels extend through the gate lines in the first direction. The contacts extend through the at least one etch-stop layer and are on the step portions of the gate lines.