An organic light emitting diode display includes a substrate, an overlap layer on the substrate, a semiconductor layer on the overlap layer, a first gate conductor on the semiconductor layer, a second gate conductor on the first gate conductor, a data conductor on the second gate conductor, a driving transistor on the overlap layer, and an organic light emitting diode connected with the driving transistor. The driving transistor includes, in the semiconductor layer, a first electrode, a second electrode, with a channel therebetween. A gate electrode of the first gate conductor overlaps the channel. The overlap layer overlaps the channel of the driving transistor and at least a portion of the first electrode. A storage line of the second gate conductor receives a driving voltage through a driving voltage line in the data conductor. The overlap layer receives a constant voltage.