A thin film transistor and a method of manufacturing the same are disclosed. More specifically, there is provided a thin film transistor having a thin film transistor and a method of manufacturing the same wherein an inorganic layer and an organic planarization layer are sequentially formed on the surface of a substrate on source/drain electrode of a thin film transistor having a semiconductor layer, a gate, source/drain areas and the source/drain electrodes, and a blanket etching process is performed to the organic planarization layer to planarize the inorganic layer. After forming a photoresist pattern on the inorganic layer, an etching process is performed to form a hole coupling a pixel electrode with one of the source/drain electrodes. According to the manufacturing method, the hole may be formed using one mask, thereby simplifying a manufacturing process, and improving an adhesion with the pixel electrode by the inorganic layer formed above. This thin film transistor may be appropriately applied to the active matrix organic electro luminescence display.