A thin film transistor (TFT) plate having improved processing efficiency without degradation in performance and a method of fabricating the TFT plate are provided. The TFT plate includes gate insulating layer patterns made of dual layers. Upper portions of both sidewalls of an upper gate insulating layer pattern are substantially aligned with both sidewalls of a gate electrode. Lower portions of both sidewalls of the upper gate insulating layer pattern are substantially aligned with a boundary portion between a lightly doped region and a source region and a boundary portion between the lightly doped region and a drain region. Thus, the concentration of the lightly doped region under a lower gate insulating layer pattern gradually changes.