A display device includes a base substrate including: a display region including a pixel, and a pad region defining an end surface of the base substrate which is furthest from the display region and exposed outside the display panel; an insulating layer in the display region and the pad region; and in the pad region: a signal pad electrically connected to the pixel and to a dummy pad; the insulating layer covering the signal pad and the dummy pad and defining an end surface of the insulating layer which is furthest from the display region and exposed outside the display panel; and a first opening in the insulating layer which exposes the signal pad outside the insulating layer and outside the display panel. In the pad region, the end surfaces of the base substrate and the insulating layer together define an inclined edge of the display panel.