A thin film transistor substrate according to an exemplary embodiment includes: a substrate; a gate electrode disposed on the substrate; a gate insulating layer disposed on the gate electrode; an oxide semiconductor disposed on the gate insulating layer; a first interlayer insulating layer disposed on the oxide semiconductor; a data line disposed on the first interlayer insulating layer; a second interlayer insulating layer disposed on the data line; a source electrode disposed on the second interlayer insulating layer and connected with the oxide semiconductor and the data line through a first contact hole through the second interlayer insulating layer; and a drain electrode disposed on the second interlayer insulating layer and connected with the semiconductor through a second contact hole through the second interlayer insulating layer.