A thin film transistor, a display device including the same, and a method of manufacturing the display device, the thin film transistor including a substrate; a gate electrode on the substrate; a gate insulating layer on the gate electrode; a semiconductor layer on the gate insulating layer; and source/drain electrodes electrically connected with the semiconductor layer, wherein the gate electrode has a thickness of about 500 Å to about 1500 Å and the gate insulating layer has a thickness of about 1600 Å to about 2500 Å.