Disclosed are a thin film transistor and a display device including the thin film transistor. The thin film transistor comprises: a bottom gate electrode on a substrate; a semiconductor layer overlapping with the bottom gate electrode, wherein the semiconductor layer comprises a N-type semiconductor layer and a P-type semiconductor layer, and the N-type semiconductor layer is overlapped partly with the P-type semiconductor layer; a first source electrode and a first drain electrode respectively connected to the P-type semiconductor layer; a second source electrode and a second drain electrode respectively connected to a portion of the N-type semiconductor layer which is not overlapped with the P-type semiconductor layer; and a top gate electrode above the semiconductor layer. According to the embodiment of the present disclosure, a complexity of a manufacturing process of the thin film transistor is reduced.