A thin film transistor substrate includes a semiconductor pattern on a base substrate, a first insulation member disposed on the semiconductor pattern, a second insulation pattern disposed on the first insulation member, and a gate electrode disposed on the first insulation member and the second insulation pattern. The second insulation pattern overlaps a first end portion of the semiconductor pattern, and exposes a second end portion of the semiconductor pattern opposite to the first end portion. The gate electrode overlaps both the first insulation member and the second insulation pattern.