The present disclosure provides a thin film transistor, including: an active layer, a source and a drain electrically coupled with the active layer, and a plurality of doped layers located between the source and the active layer and between the drain and the active layer, a resistance of one of the plurality of doped layers farthest away from the active layer is smaller than that of any other doped layer. The disclosure further provides a gate driving circuit, a display substrate and a display device. With the present disclosure, current loss of a current passing through the doped layers of the thin film transistor is reduced, on-state current of the thin film transistor is improved and a situation that output signals of the thin film transistor are insufficient is avoided.