A thin film transistor includes: a gate electrode; source and drain electrodes insulated from the gate electrode; an organic semiconductor layer that is insulated from the gate electrode and is electrically connected to the source and drain electrodes; an insulating layer that insulates the gate electrode from the source and drain electrodes or the organic semiconductor layer; and an ohmic contact layer that is interposed between the source/drain electrodes and the organic semiconductor and contains a compound having a hole transporting unit. By providing the ohmic contact layer, the ohmic contact between source/drain electrodes and the organic semiconductor layer can be effectively achieved and the adhesive force between the source/drain electrodes and the organic semiconductor layer is increased. In addition, a flat panel display having improved reliability can be obtained using the thin film transistor.