Embodiments of the present invention relate to a thin film transistor and a manufacturing method of a display panel, and include forming a gate line including a gate electrode on a substrate, forming a gate insulating layer on the gate electrode, forming an intrinsic semiconductor on the gate insulating layer, forming an extrinsic semiconductor on the intrinsic semiconductor, forming a data line including a source electrode and a drain electrode on the extrinsic semiconductor, and plasma-treating a portion of the extrinsic semiconductor between the source electrode and the drain electrode to form a protection member and ohmic contacts on respective sides of the protection member. Accordingly, the process for etching the extrinsic semiconductor and forming an inorganic insulating layer for protecting the intrinsic semiconductor may be omitted such that the manufacturing process of the display panel may be simplified, manufacturing cost may be reduced, and productivity may be improved.