A display device includes a first substrate having a display area and a non-display area adjacent to the display area, the first substrate including a substrate through-hole penetrating the first substrate in a thickness direction, an etching stopper disposed on a first surface of the first substrate, the etching stopper including a stopper through-hole that overlaps the substrate through-hole and penetrates the etching stopper in the thickness direction, a data line disposed on the etching stopper, a substrate connection electrode that fills the substrate through-hole and the stopper through-hole, the substrate connection electrode being disposed in the display area and electrically connected to the data line, and a first pad disposed on a second surface of the first substrate opposite to the first surface and overlapping the substrate connection electrode. The first pad is electrically connected to the substrate connection electrode.