A gate driving unit includes a plurality of stages sequentially outputting a plurality of gate signals, wherein each of the plurality of stages includes a first transistor including: a gate electrode; a gate insulating layer on the gate electrode; and a source electrode and a drain electrode on the gate insulating layer over the gate electrode, the source electrode and the drain electrodes spaced apart from each other, and wherein a first area where the gate electrode and the source electrode overlap each other is 2.5 times to 6 times of a second area where the gate electrode and the drain electrode overlap each other.