Oreochromis is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very small ranges; some are seriously threatened, and O. ismailiaensis and O. lidole possibly are extinct. Although Oreochromis primarily are freshwater fish of rivers, lakes and similar habitats, several species can also thrive in brackish waters and some even survive in hypersaline conditions with a salinity that far surpasses that of seawater. In addition to overfishing and habitat loss, some of the more localized species are threatened by the introduction of other, more widespread Oreochromis species into their ranges. This is because they—in addition to competing for the local resources—often are able to hybridize.

Oreochromis are fairly robust fish, and medium–small to very large cichlids that can reach up to 9.4–61 cm (4–24 in) in total length depending on the exact species.

The earliest known member of this group is Oreochromis lorenzoi Carnevale, Sorbini & Landini, 2003 from the latest Miocene (Messinian) of Italy, suggesting that this genus naturally ranged as far north as southern Europe in prehistoric times.

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