Provided is a memory device. The memory device may include a substrate, a ferroelectric field effect transistor disposed on the substrate, a first channel contacting a gate structure of the ferroelectric field effect transistor and extending in a vertical direction from the gate structure of the ferroelectric field effect transistor, a selection word line disposed at one side of the first channel, a first gate dielectric layer disposed between the first channel and the selection word line, and a cell word line disposed on top of the first channel.