The ʻōʻū (pronounced [ˈʔoːʔuː]) (Psittirostra psittacea) is an extinct species of Hawaiian honeycreeper that was endemic to the Hawaiian islands. It had a dark green back and olive green underparts; males had a yellow head while females had a green head. Its unusual beak seems to have been adapted to feeding on the fruits of Freycinetia arborea. It had a strong flight which it used to fly considerable distances in search of this vine, but it also ate other fruits, buds, flowers and insects.

Although formerly widespread and present throughout the island group, numbers declined dramatically during the twentieth century. The bird is listed by the International Union for Conservation of Nature as being Critically Endangered, but there are no recent records and it may be extinct. The last recorded sighting was in 1989. The U.S. Fish and Wildlife Service declared the species extinct in a 2022 study review. In 2024, the International Union for Conservation of Nature declared the species extinct.

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