With 82-88% of the population depending on who you ask, Islam is by far the largest religion in Indonesia, making Indonesia the largest Muslim-majority state in the world. Indonesia's brand of Islam is generally quite tolerant and in larger cities headscarves and such visible manifestations of faith are exceptions rather than the rule, although the countryside and the devout state of Aceh can be considerably stricter.

The other state-sanctioned religions are Protestantism (5%), Roman Catholicism (3%), Hinduism (2%) and Buddhism (1%). Hindus are concentrated on Bali, while Christians are found mostly in Sulawesi and East Nusa Tenggara. There are also pockets of animism throughout the country, and many strict Muslims decry the casual Javanese incorporation of animistic rites into the practices of notionally Islamic believers.