A display device including: a display region including a first pixel region, a second pixel region, and a third pixel region; a dummy region including a first dummy region disposed between the second pixel region and the third pixel region; first, second, and third pixels respectively arranged in the first pixel region, the second pixel region, and the third pixel region in a matrix of vertical lines and horizontal lines; a data converter configured to receive first image data including effective data corresponding to the display region and dummy data corresponding to the dummy region and generate second image data by converting a gray scale value of dummy data corresponding to at least one region of the first dummy region in the first image data into a predetermined first gray scale value, the first gray scale value being between a lowest gray scale value and a highest gray scale value.