Among religions in Brunei, Sunni Islam is predominant. In 2021, the government census showed that 82.1% of Brunei's population is Muslim. However, other religions also have a considerable foothold in Brunei: 8.7% of the population is Christian and another 7.8% is Buddhist. The remaining 5% subscribe to various religions, including indigenous religions.^[2]

Islam is the state religion of Brunei, but freedom of religion is guaranteed. This freedom however, is limited for several cases.^[3] The right to practice privately is given to a plethora of religions.^[3] Furthermore, some non-Islamic holidays, such as Lunar New Year, Christmas, Vesak day and Gawai Dayak, are recognised.^[3] These rights however, are limited: religious education is controlled, even in the Chinese, Christian and private schools, and any non-Islamic religious materials being distributed are gazetted as illegal and tightly forbidden; where if caught it will result in an immediate death punishment without judgment and the involved materials are subject to confiscation, based on the 2014 Shariah Penal Code Ordinance.^[3]

The state madh'hab of Islam is the Shafi'i school of jurisprudence of Sunni Islam.^[4] Most of Brunei's Muslim population subscribe to the Shafi'i school as well, and Shafi'i is a major source of law for the country.^[4] However, with the Sultan's permission, lawmakers may also consult the other three Sunni schools of fiqh.^[4]

In Brunei, non-Muslims must be at least 14 years and 7 months old if they want to convert to another religion. A minor will automatically become a Muslim if his parents convert to Islam.^[5]