A display device includes a main display unit for displaying main images by processing main image data in response to main gate signals, a sub display unit for displaying sub images by processing sub image data in response to sub gate signals, a connection part for connecting the main and sub display units, a driver for providing the main image data and the main gate signals to the main display unit and the sub image data and the sub gate signals to the sub display unit, first connection lines disposed between the driver and the sub display unit to transfer the sub gate signals to the sub display unit, second connection lines disposed between the driver and the sub display unit to transfer the sub image data to the sub display unit, and a dummy line disposed between the first connection lines and an image display region of the main display unit.