An organic light emitting diode display is disclosed that includes at least a shield layer on a substrate; a semiconductor layer on the shield layer; a gate insulating layer on the semiconductor layer; a gate electrode on the gate insulating layer; a connection electrode disposed on the same layer as the gate electrode, the connection electrode electrically connected to the shield layer; a source electrode and a drain electrode on the gate electrode, at least one of the drain and source electrodes electrically connected to the semiconductor layer and the connection electrode; an insulating layer on the drain electrode and the source electrode; and a first electrode on the insulating layer and electrically connected to the source electrode.