An organic thin film transistor (TFT) that allows an organic semiconductor layer to be easily patterned includes a gate electrode, source and drain electrodes insulated from the gate electrode, a self-assembly monolayer formed on the source and drain electrodes, an organic semiconductor layer which is insulated from the gate electrode and covers at least a portion of the self-assembly monolayer. A flat panel display apparatus includes the organic TFT. A method of manufacturing an organic TFT includes forming source and drain electrodes on a substrate; forming a self-assembly monolayer covering at least the source and drain electrodes; patterning the self-assembly monolayer to remove portions of the self-assembly monolayer that are not located on the source and drain electrodes; and forming an organic semiconductor layer by inkjet printing an organic semiconductor material between the source and drain electrodes.