The present invention relates to a thermally curable resin composition for a protective film including an alkoxy group-containing silane-modified epoxy resin as an essential component, a protective film of a color filter prepared from the same, and a liquid crystal display device including the same. The thermally curable resin composition for a protective film of the present invention includes an alkoxy group-containing silane-modified epoxy resin as an essential component to have excellent film strength and adhesive strength, and thus may be effectively used in a protective film of a color filter for a liquid crystal display device.