A TFT having a dual buffer structure, a method of fabricating the same, and a flat panel display having the TFT, and a method of fabricating the same are provided. The TFT includes a first buffer layer formed of an amorphous silicon layer on a substrate, a second buffer layer formed on the first buffer layer. The TFT also includes a semiconductor layer formed on the second buffer layer and a gate electrode formed on the semiconductor layer. The dual buffer structure provides better barrier to impurities diffusing from the substrate, and also acts as a black matrix to reduce unwanted reflections and is a source of hydrogen to passivate other layers.