An organic light-emitting diode (OLED) display is disclosed. In one aspect, the display includes a substrate and an active pattern formed over the substrate and including first to fourth regions. A gate insulation layer is formed over the active pattern and the substrate, and a first gate electrode is formed over the gate insulation layer and partially overlapping the active pattern. The first gate electrode, the first region and the second region define a first transistor. A second gate electrode is formed on the same layer as the first gate electrode. The second gate electrode, the third region and the fourth region define a second transistor, and the second gate electrode, the second region and the fourth region define a third transistor. A first insulating interlayer is formed over the first gate electrode, the second gate electrode, and the gate insulation layer.