A thin film transistor including a gate electrode; an active layer insulated from the gate electrode; a source electrode and a drain electrode that are insulated from the gate electrode and are electrically connected to the active layer; a first etch stopper layer that is formed of an insulation material and contacts a portion of the active layer located between areas of the active layer that are electrically connected to the source electrode and the drain electrode; a second etch stopper layer on the first etch stopper layer, the second etch stopper layer being formed of an insulation material of a same type as the insulation material used to form the first etch stopper layer, the second etch stopper layer having a higher density than the first etch stopper layer; and a third etch stopper layer on the second etch stopper layer.