A photosensitive resin composition is provided. The composition includes an acrylic copolymer, a photoacid generator and a solvent. The acrylic copolymer includes structural units of Formulae 1, 2, 3 and 4, which are described in the specification. The composition exhibits excellent performance characteristics in terms of mechanical and thermal properties, transmittance, insulating properties, transparency, developability, residual film ratio, heat resistance, flatness and the like. Particularly, the use of the composition facilitates the formation of a pattern as an interlayer insulating film. The composition can also be used to produce a thick film with high transmittance. Therefore, the composition is effectively used as a material for an interlayer insulating layer in LCD fabrication processes. An organic insulating film produced using the composition is also provided.