A display device includes a substrate including a display area and a non-display area, a plurality of pixels provided in the display area, lines respectively connected to the plurality of pixels, the lines applying a signal to the plurality of pixels, the lines each including a first metal layer including a first metal and a second metal layer that is provided on the first metal layer and includes a second metal, an insulating layer provided at a least one portion between the substrate and the lines, the insulating layer including an inorganic insulating layer and an organic insulating layer, and a barrier layer provided between the organic insulating layer and the first metal layer, the barrier layer including an oxide of the first metal.