Heliconius ethilla, the ethilia longwing, is a butterfly of the Nymphalidae family. It was described by Godart in 1819. It is found from Panama to southern Brazil. The habitat consists of marginal forests. The wingspan is 60–70 mm. The forewings are orange with a black margin and four black spots. The hindwings are orange with two black stripes. The larvae feed on Passiflora species. Full-grown larvae have a white body with an orange head and reach a length of about 17 mm.