Disclosed is a composition, an organic insulating film including the same, an organic thin film transistor including the organic insulating film, an electronic device including the organic thin film transistor and methods of fabricating the same. In the composition, an organic polymer material having a carboxyl group and an organic silane material having an electron-donating group are included to thus realize a structure which may further stabilize an unreacted crosslinking material. Thereby, a hysteresis phenomenon may be decreased and transparency may be increased, thus making it possible to assure stability upon exposure to air. Accordingly, the lifetime of the organic thin film transistor may be lengthened.