Papilio ornythion, the ornythion swallowtail, is a swallowtail butterfly of the subfamily Papilioninae. It is found in Mexico and Guatemala. It is occasionally recorded from central and southern Texas and New Mexico and rarely from southern Arizona and Kansas. The wingspan is 83–115 millimetres (3.3–4.5 in). Adults are on wing from April to September. There are probably two generations per year. The larvae feed on the leaves of Citrus trees. Adults feed on flower nectar.