The American flamingo (Phoenicopterus ruber) is a large species of flamingo native to the West Indies, northern South America (including the Galápagos Islands) and the Yucatán Peninsula. It is closely related to the greater flamingo and Chilean flamingo, and was formerly considered conspecific with the greater flamingo, but that treatment is now widely viewed (e.g. by the American and British Ornithologists' Unions) as incorrect due to a lack of evidence. It is also known as the Caribbean flamingo, although it is also present in the Galápagos Islands. It is the only flamingo that naturally inhabits North America along with the Neotropical realm.

It is a cultural icon for the U.S. state of Florida, where it was formerly abundant in the southernmost regions, although it was largely extirpated by 1900 and is now only an uncommon visitor with a few small, potentially resident populations.

The American flamingo was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the current binomial name Phoenicopterus ruber. Linnaeus cited earlier authors including the English naturalist Mark Catesby who in 1729–1731 had described and illustrated the flamingo found on the Bahamas islands. Linnaeus specified the type locality as "Africa, America, rarius in Europe" but the locality was restricted to the Bahamas by the German ornithologist Hans von Berlepsch in 1908. The genus name Phoenicopterus is the Latin word for a flamingo. The specific epithet ruber is Latin meaning "red". The greater flamingo (Phoenicopterus roseus), that is widespread in the Old World, was formerly treated as a subspecies of the American flamingo. Molecular phylogenetic studies have shown that the two taxa are each other's closest relatives.

Two subspecies are recognised:

The American flamingo breeds in South America (in the Galápagos Islands of Ecuador, coastal Colombia and Venezuela, and northern Brazil), in the West Indies (Trinidad and Tobago, Cuba, Jamaica, Hispaniola (the Dominican Republic and Haiti), The Bahamas, the Virgin Islands, and the Turks and Caicos Islands), and tropical and subtropical areas of continental North America (along the northern coast of the Yucatán Peninsula in Mexico, and formerly southern Florida in the United States). It is a vagrant to Puerto Rico, Anguilla, Barbados, Honduras, and (following its extirpation) Florida, although some Florida populations are now thought to be year-round residents. The population in the Galápagos Islands differs genetically from that in the Caribbean; the Galápagos flamingos are significantly smaller, exhibit sexual dimorphism in body shape, and lay smaller eggs. They are sometimes separated as Phoenicopterus ruber glyphorhynchus.

Marine biologists say that, although flamingos are native to the tropical south of the U.S., hurricanes have been known to drive flocks of flamingos north, leading to rare sightings in Kentucky, New York, Ohio, Pennsylvania and Virginia. Most of the birds return to where they came from, but occasionally, one breaks off from a flock so that there are examples of a flamingo hanging out by itself for years.

Its preferred habitats are similar to those of its relatives: saline lagoons, mudflats, and shallow, brackish coastal or inland lakes. An example habitat is the Petenes mangroves ecoregion of the Yucatán.

The American flamingo is considered an iconic symbol of the state of Florida in the United States, and is widely featured on merchandise from the state. Although the species was a former resident and a possible breeder in Florida until the early 20th century, the strong association of flamingos with Florida likely originates from the Flamingo Hotel, a popular 1920s hotel in Miami Beach, which was named after an exotic bird for marketing purposes. The hotel's strong association with South Florida led to the popularity of flamingo souvenirs from the state, which was further boosted by the captive flamingos kept in Hialeah Park.