Islam is Brunei's official religion, 64 percent of the population is Muslim. mostly Sunnis of Malay origin who follow the Shafi school of Islamic law. Most of the other Muslim groups are Kedayans (converts from indigenous tribal groups) and Chinese converts.

The Great Mosque in Brunei

Islam was adopted in the 15th century when a Malay Muslim was installed as sultan. The sultan traditionally was responsible for upholding Islamic traditions, although the responsibility was usually delegated to appointed officials.

Since the 1930s sultans have used rising oil revenues to provide an extensive social welfare system and promote Islam, including subsidizing the Hajj, building mosques, and expanding the Department of Religious Affairs.