Tilapia is a large genus belonging to the tribe Tilapiini in the family Cichlidae. Tilapia thus belong to the same family as many famous aquarium species, such as Angelfish, Discus, and Oscarfish. A few examples of cichlid species belonging to the genus Tilapia are Guinean tilapia (Tilapia guineensis), Spotted tilapia (Tilapia mariae), Otjikoto tilapia (Tilapia guinasana), and Okavango tilapia (Tilapia ruweti).

True tilapias are found in the genus Tilapia, but many other members of the tribe Tilapiini are referred to as tilapias in everyday speech.

The name tilapia is derived from thiape, the Tswana word for fish. (Tswana is an African language; it belongs to the Bantu language group.) The genus was named by Andrew Smith, a Scottish zoologist and explorer, in 1840.

The genus Tilapia currently contains about 40 described species, but used to be considerably larger in the past. Many species once considered a part of Tilapia has been moved to the genera Oreochromis and Sarotherodon, and the genus Tilapia might grow even smaller in the future as this part of the cichlid family become more thoroughly explored by science. It is however very difficult to interpret the results of mitochondrial DNA (mtDNA) sequence analysis when it comes to the tribe Tilapiini since these species readily mate with each other in the wild; matings which frequently results in fertile offspring. The interpretation is further complicated by the fast pace of evolution observed in Tilapiini fish.

From its native region, tilapia fish has today spread into many other parts of the world, aided by man. The genus tilapia contains a rich assortment of popular food fishes, many of which are grown in aquacultures. When tilapia is released into the wild or escapes from tilapia farms, it can cause severe problems for the native ecosystem as an invasive species.