Provided are a thin film transistor and a method of manufacturing the same. The thin film transistor includes: a lower structure; a semiconductor layer formed on the lower structure and including a plurality of doping regions; a first insulating layer and a second insulating layer formed on the semiconductor layer and separated from each other; a third insulating layer formed on the first insulating layer and the second insulating layer; and a gate electrode layer formed between regions of the third insulating layer respectively corresponding to the first insulating layer and the second insulating layer.