A thin film transistor may include an active layer formed on an insulating substrate and formed with source/drain regions and a channel region; a gate insulating film formed on the active layer; and a gate electrode formed on the gate insulating film. The gate electrode may be formed of a conductive metal film pattern and a conductive oxide film covering the conductive metal film pattern. The source/drain regions may include an LDD region, and the LDD region may at least partially overlap with the gate electrode.