A resin composition is provided, which satisfies both an uncured layer flexibility requirement and a patterning resolution requirement for production of an optical waveguide by a roll-to-roll process. An optical waveguide produced by using the resin composition is also provided. The resin composition comprises: (A) an aromatic multifunctional epoxy polymer having a weight average molecular weight (Mw) of 500 to 5000; (B) an aromatic multifunctional epoxy polymer having a weight average molecular weight (Mw) of 10000 to 50000; (C) at least one of monofunctional, difunctional and trifunctional liquid aromatic epoxy monomers; and (D) a photoacid generator; wherein the components (A), (B) and (C) are present in proportions of 80 to 90 parts by weight, 5 to 15 parts by weight, and 1 to 10 parts by weight, respectively, based on a total of 100 parts by weight of the components (A), (B) and (C).