Sinhalese, member of a people of Sri Lanka (formerly Ceylon) who constitute the largest ethnic group of that island. In the early 21st century the Sinhalese were estimated to number about 13.8 million, or 73 percent of the population. Their ancestors are believed to have come from northern India, traditionally in the 5th century bce. Their language belongs to the Indo-European family.

Most Sinhalese are agriculturalists. The low-country Sinhalese of the southern and western coastal regions have been heavily influenced by European culture, while the Kandyan Sinhalese of the highlands are more traditional. The Sinhalese are Theravada Buddhists except for a Christian minority.

Like other peoples of Sri Lanka, the Sinhalese constitute a caste-based society with a complex structure historically founded largely on occupation. Differences in religious and other customary practices are minimal between the castes. Marriage is generally endogamous within the same caste, with spouses drawn preferably from the children of the mother’s brother or father’s sister. Monogamy is the rule, as polygyny and polyandry were declared illegal in the mid-19th century.