A display device and a driving method thereof are disclosed. In one aspect, the display device includes a plurality of pixels, each including a driver which generates a driving current according to an input image data signal and a light emission portion formed of an organic light-emitting diode which emits light according to the driving current and at least one dummy pixel connected to a repair line that is connected to a light emission portion of at least one first pixel among the plurality of pixels. The dummy pixel includes a dummy pixel driver having the same structure as the drivers of each of the plurality of pixels, a dummy pixel light emission portion formed of an organic light-emitting diode, and a repair driver which transmits a driving current generated in the dummy pixel driver through the repair line when a driver of the first pixel fails.