Disclosed is a thin film transistor substrate comprising a substrate; a first thin film transistor on the substrate, the first thin film transistor including a first active layer and a first gate electrode; a second thin film transistor on the substrate, the second thin film transistor including a second active layer and a second gate electrode above the first active layer and the first gate electrode; a first insulating layer between the first gate electrode and the second active layer; and; and a first connection electrode connecting together the first active layer and the second active layer, the first connection electrode extending through a first contact hole in the first insulating layer and is in contact with each of the first active layer and the second active layer and a display apparatus including the same.