The red-winged blackbird is one of 11 species in the genus Agelaius and is included in the family Icteridae, which is made up of passerine birds found in North and South America. The red-winged blackbird was originally described as Oriolus phoeniceus by Linnaeus in his 18th-century work, Systema Naturae, but was later moved with the other American blackbirds to the genus Agelaius (Vieillot, 1816). The genus name is Latin derived from Ancient Greek, agelaios, meaning "belonging to a flock". The specific epithet, phoeniceus, is from the Latin word meaning "deep red".
In the California subspecies, A. p. californicus and A. p. mailliardorum, the veining of the female specimens also covers a smaller surface and the plumage is dark brown. The male subspecies mailliardorum, californicus, lacks the yellow band on the wing that are present in most male members of the species.