A display device may include a display panel including a substrate that includes a display area and a pad area adjacent to the display area, and a first pad and a second pad on the pad area of the substrate, and a chip-on-film package over the pad area of the substrate with the first pad and the second pad in between, the chip-on-film package including an insulation layer, a first wiring on an upper surface of the insulation layer and electrically connected to the first pad, and a second wiring on a lower surface of the insulation layer and electrically connected to the second pad. A first signal having alternating voltage levels may be applied to the first wiring, and a second signal having a constant voltage level may be applied to the second wiring.