A display device includes at least one transistor. The transistor has an active pattern including a first active area and a second active area. The first active area includes a first channel area and an n-doped area contacting the first channel area. The second active area includes a second channel area and a p-doped area contacting the second channel area. A first insulation layer covers at least a portion of the active pattern. A first gate electrode is disposed on the first insulation layer and at least partially overlaps the first channel area. A second gate electrode is disposed on the first insulation layer and at least partially overlaps the second channel area. A taper angle of the second gate electrode is larger than a taper angle of the first gate electrode.