The Malayo-Polynesian languages are a subgroup of the Austronesian languages, with approximately 385.5 million speakers. The Malayo-Polynesian languages are spoken by the Austronesian peoples outside of Taiwan, in the island nations of Southeast Asia (Indonesia and the Philippine Archipelago) and the Pacific Ocean, with a smaller number in continental Asia in the areas near the Malay Peninsula, with Cambodia, Vietnam and the Chinese island Hainan as the northwest geographic outlier. Malagasy, spoken on the island of Madagascar off the eastern coast of Africa in the Indian Ocean, is the furthest western outlier.

Many languages of the Malayo-Polynesian family in insular Southeast Asia show the strong influence of Sanskrit, Tamil and Arabic, as the western part of the region has been a stronghold of Hinduism, Buddhism, and, later, Islam.

Two morphological characteristics of the Malayo-Polynesian languages are a system of affixation and reduplication (repetition of all or part of a word, such as wiki-wiki) to form new words. Like other Austronesian languages, they have small phonemic inventories; thus a text has few but frequent sounds. The majority also lack consonant clusters. Most also have only a small set of vowels, five being a common number.

All major and official Austronesian languages belong to the Malayo-Polynesian subgroup. Malayo-Polynesian languages with more than five million speakers are: Indonesian, Javanese, Sundanese, Tagalog, Bikol, Malagasy, Malay, Cebuano, Madurese, Ilocano, Hiligaynon, and Minangkabau. Among the remaining more than 1,000 languages, several have national/official language status, e.g. Tongan, Samoan, Māori, Gilbertese, Fijian, Hawaiian, Palauan, and Chamorro.

The term "Malayo-Polynesian" was originally coined in 1841 by Franz Bopp as the name for the Austronesian language family as a whole, and until the mid-20th century (after the introduction of the term "Austronesian" by Wilhelm Schmidt in 1906), "Malayo-Polynesian" and "Austronesian" were used as synonyms. The current use of "Malayo-Polynesian" denoting the subgroup comprising all Austronesian languages outside of Taiwan was introduced in the 1970s, and has eventually become standard terminology in Austronesian studies.

In spite of a few features shared with the Eastern Formosan languages (such as the merger of proto-Austronesian *t, *C to /t/), there is no conclusive evidence that would link the Malayo-Polynesian languages to any one of the primary branches of Austronesian on Taiwan.

Malayo-Polynesian consists of a large number of small local language clusters, with the one exception being Oceanic, the only large group which is universally accepted; its parent language Proto-Oceanic has been reconstructed in all aspects of its structure (phonology, lexicon, morphology and syntax). All other large groups within Malayo-Polynesian are controversial.

The most influential proposal for the internal subgrouping of the Malayo-Polynesian languages was made by Robert Blust who presented several papers advocating a division into two major branches, viz. Western Malayo-Polynesian and Central-Eastern Malayo-Polynesian.