Indonesia has no state religion, yet for decades every ID card named one
The country with the world's biggest Muslim population also built Borobudur, the largest Buddhist monument anywhere. Indonesia's founding philosophy asks citizens to believe in one almighty God without naming which. From 1965 the state recognised six faiths, and until 2017 everyone had to pick one of them for their identity card.
Before the Common Era the islands followed local Austronesian and Papuan beliefs. Indian traders brought Hinduism around the second century and Buddhism around the fourth, landing on Sumatra, Java and Sulawesi. Kingdoms such as Srivijaya and Majapahit grew under their influence; the Shailendra dynasty raised Borobudur, and the Hindu temple complex of Prambanan went up in the same era. Majapahit in the fourteenth century is remembered as a golden age of Hindu-Javanese civilisation.
Arab Muslim merchants may have arrived by the 8th century, and Marco Polo noted a Muslim trading community at Perlak in Aceh around 1297. Islam spread along Sumatra's coasts and then east into Java, carried by preachers such as Maulana Malik Ibrahim and by sultans who fought Hindu-Buddhist states and one another. Some communities adapted Islam to older customs, while Hindus from western Java withdrew to Bali, which remains largely Hindu. Portuguese missionaries brought Catholicism to Flores in the 16th century, and the Dutch East India Company steered Protestant missions toward the animist east and away from Muslim Java.
A presidential edict of January 1965 listed six recognised religions: Islam, Catholicism and Protestantism counted separately, Hinduism, Buddhism and Confucianism, while stating that faiths such as Judaism, Shinto and Taoism were not banned. After the attempted coup that year, the New Order made religious affiliation compulsory to root out suspected communists, many of whom were nominal Muslims. That pushed large numbers into Christianity, as did the exclusion of Confucianism for many Chinese Indonesians. A 2017 Constitutional Court ruling finally let people leave the religion box blank or list indigenous beliefs.
Home Affairs Ministry figures for 2025 put Muslims at 87.15% of the population, almost all Sunni of the Shafi'i school, and Christians at 10.44%. The Muslim majority divides broadly into traditionalists and modernists, represented by the two giant organisations Nahdlatul Ulama and Muhammadiyah. Blasphemy has been a crime since 1965, atheism is not recognised, and Aceh province applies Sharia.
Source: Religion in Indonesia
