A vertical memory device includes a gate electrode structure, channels, a charge storage structure, and a division pattern. The gate electrode includes gate electrodes spaced apart from each other in a first direction. The channel extends through the gate electrode structure, and includes a first portion and a second portion on and contacting the first portion. The second portion includes a lower surface having a width less than that of an upper surface of the first portion. The charge storage structure covers an outer sidewall of the channel. The division pattern extends between the channels in a second direction, and includes a first dummy channel and a first dummy charge storage structure covering a sidewall and a lower surface thereof. The first dummy channel includes the same material as that the channel, and the first dummy charge storage structure includes the same material as the charge storage structure.