Example embodiments of the present invention relate to an organic insulator composition, an organic insulating film having the organic insulator composition, an organic thin film transistor having the organic insulating film, an electronic device having the organic thin film transistor and methods of forming the same. Other example embodiments of the present invention relate to an organic insulator composition including a fluorinated silane compound that may be used to improve the charge carrier mobility and hysteresis of an organic thin film transistor. An organic insulator composition including a fluorinated silane compound and an organic thin film transistor using the same is provided. The hysteresis and physical properties, e.g., threshold voltage and/or charge carrier mobility, of the organic thin film transistor may be improved by the use of the organic insulator composition. The organic thin film transistor may be effectively used in the manufacture of a variety of electronic devices including liquid crystal displays (LCDs) and/or photovoltaic devices.