A thin film transistor (TFT) includes a scan line on a substrate, the scan line including a straight portion extending along a first direction, an active layer including an oxide semiconductor and overlapping the straight portion of the scan line, the active layer having a first region, a second region, and a third region that are linearly and sequentially aligned along the first direction, a first insulating layer between the active layer and the scan line, a first electrode connected to the first region of the active layer, and a second electrode connected to the third region of the active layer.