A vertical memory device including: a circuit pattern on a first substrate; an insulating interlayer on the first substrate, the insulating interlayer covering the circuit pattern; a bending prevention layer on the insulating interlayer, the bending prevention layer extending in a first direction substantially parallel to an upper surface of the first substrate; a second substrate on the bending prevention layer; gate electrodes spaced apart from each other in a second direction on the second substrate, the second direction being substantially perpendicular to the upper surface of the first substrate; and a channel extending through the gate electrodes in the second direction.