A thin film transistor array panel according to an exemplary embodiment of the present invention includes: a gate electrode disposed on an insulation substrate; a gate insulating layer disposed on the gate electrode; a semiconductor disposed on the gate insulating layer; an etching stop layer disposed on the semiconductor; an insulating layer disposed on the gate insulating layer; and a source electrode and a drain electrode overlapping the semiconductor. The semiconductor and the gate insulating layer have a first portion on which the etching stop layer and the insulating layer are disposed, and a second portion on which etching stop layer and the insulating layer are not disposed. The source electrode and the drain electrode are disposed on the second portion of the semiconductor and the gate insulating layer.