Presbyornis is an extinct genus of presbyornithid bird from North America during the Paleogene period, between the Late Paleocene and Early Eocene.

[2] The fossil record of P. pervetus includes many complete skeletons from Green River Formation sites (Early Eocene), suggesting that the birds nested in colonies and that they possibly died due to volcanism or botulism, the latter of which is similar to many colony-nesting waterfowl or shorebirds today.

[10] P. recurvirostra is known from a partial wing (KUVP 10105) found in the Colton Formation, from the Late Paleocene to Early Eocene sediments of the Wasatch Plateau near Ephraim, Utah.

[13] The holotype and paratypes of "P." mongoliensis are known from the Early Eocene of Mongolia,[4] but these fragmentary specimens are poorly preserved and they likely belong to a stem Phoenicopterimorphae, not a presbyornithid.

[3] Because of its long legs and neck, Presbyornis could stand up to 1 metre (3.3 ft) tall and was initially mistaken for a flamingo, but it was reclassified as an anseriform when the duck-like anatomy of its skull and bill was found.