A display device includes a substrate that includes a display area and a peripheral area, a transistor in the display area, a pixel electrode connected to the transistor, a common electrode that overlaps the pixel electrode, and an organic insulation layer that is between the common electrode and the substrate, and overlaps at least a part of the peripheral area, wherein a thickness of a portion of the organic insulation layer overlapping the display area, and a thickness of a portion of the organic insulation layer overlapping the peripheral area, are different from each other, and the organic insulation layer includes a valley that penetrates the organic insulation layer, while overlapping the peripheral area.