The present invention has an object to provide a photosensitive resin composition for optical waveguide formation, which has low transmission loss and can form a waveguide pattern with high shape accuracy at low cost; an optical waveguide; and a method for producing an optical waveguide. The present invention provides a photosensitive resin composition for optical waveguide formation comprising at least: a polymer containing at least a (meth)acrylate structure unit having an epoxy structure, and a (meth)acrylate structure unit having a lactone structure and/or a vinyl monomer structure unit having an aromatic structure; and a photoacid generator, of which one or both of a core layer and a cladding layer are formed of a cured product.