A thin film transistor includes a gate electrode, a semiconductor layer overlapped with the gate electrode, a gate insulating layer between the gate electrode and the semiconductor layer, and a source electrode and a drain electrode electrically connected to the semiconductor layer. The semiconductor layer includes a plurality of holes. The gate insulating layer may include a plurality of recess portions at a surface of the gate insulating layer facing the semiconductor layer. A method of manufacturing the thin film transistor is provided. A thin film transistor array panel and an electronic device may include the thin film transistor.