one of the three principal ethnic groups of the island of Java, Indonesia. The Sundanese, estimated to number about 25,850,000 in the late 20th century, are a highland people of western Java, distinguished from the Javanese mainly by their language and their strict adherence to the Muslim faith.

Historically they were first recorded under the Indo-Javanese Brahmanical states (8th century AD) and subsequently accepted the Mahāyāna Buddhism adopted by the Shailendra kings. Muslim trade influenced them to accept Islām in the 16th century, the people of Bantam being especially fervent; however, animistic and Hindu influences survive.

The Sundanese village is ruled by a headman and a council of elders. The single-family houses are made of wood or bamboo, raised on piling. Rice culture and ironworking, as well as marriage, birth, and death ceremonies, conform closely to the Javanese pattern, though often mixed with elements of Hindu origin. The Sundanese language, like Javanese, has status styles: kasar (informal), halus (deferential), and panengah (a middle style).

The opening of roads into the highlands, development of the plantation economy, and the establishment of village schools have tended to erase differences between the Sundanese and other peoples of Java. They have spread into central Java and into the Lampung area of southern Sumatra.