The Austro-Asiatic (Austroasiatic) languages, in recent classifications synonymous with Mon–Khmer, are a large language family of Southeast Asia, also scattered throughout India and Bangladesh. The name Austro-Asiatic comes from the Latin words for "south" and "Asia", hence "South Asia". Among these languages, only Khmer, Vietnamese, and Mon have a long-established recorded history, and only Vietnamese and Khmer have official status (in Vietnam and Cambodia, respectively). The rest of the languages are spoken by minority groups. Ethnologue identifies 168 Austro-Asiatic languages. These form thirteen established families (plus perhaps Shompen, which is poorly attested, as a fourteenth), which have traditionally been grouped into two, as Mon–Khmer and Munda. However, several recent classifications have abandoned Mon–Khmer as a valid node, either reducing it in scope or making it synonymous with the larger family (Diffloth 2005, Sidwell 2009).

Austro-Asiatic languages have a disjunct distribution across India, Bangladesh and Southeast Asia, separated by regions where other languages are spoken. It is widely believed^{[citation needed]} that the Austro-Asiatic languages are the autochthonous languages of Southeast Asia and the eastern Indian subcontinent, and that the other languages of the region, including the Indo-European, Tai–Kadai, Dravidian, Austronesian, and Sino-Tibetan languages, are the result of later migrations of people.