An oxide thin film transistor and a method of manufacturing the oxide TFT are provided. The oxide thin film transistor (TFT) including: a gate; a channel formed to correspond to the gate, and a capping layer having a higher work function than the channel; a gate insulator disposed between the gate and the channel; and a source and drain respectively contacting either side of the capping layer and the channel and partially on a top surface of the capping layer.