A transistor display panel including a substrate, a gate line disposed on the substrate and extending in a first direction, a gate electrode protruding from the gate line, a gate insulating layer disposed on the gate line and the gate electrode, a semiconductor layer and an auxiliary layer disposed on the gate insulating layer and spaced apart from each other, a data line disposed on the gate insulating layer and extending in a second direction which is a direction crossing the gate line, a drain electrode disposed on the gate insulating layer and the semiconductor layer and spaced apart from the data line, and a pixel electrode connected to the drain electrode, in which the auxiliary layer overlaps an edge of the gate electrode in a plan view.