A display device includes an active layer in a display area, a first gate insulation layer on the active layer, a first gate line on the first gate insulation layer in the display area, a first signal line in the same layer as the first gate line in a non-display area and including the same material as that of the first gate line including molybdenum, a second gate insulation layer on the first gate line and the first signal line, a second gate line on the second gate insulation layer in the display area, and a second signal line in the same layer as the second gate line in the non-display area and including the same material as that of the second gate line including aluminum or an aluminum alloy. A width of the first signal line is greater than a width of the second signal line.