Indonesia is the world's largest Muslim-majority country by population, around 87 percent Muslim per Pew Research's Religious Composition of the World, 2010-2020, overwhelmingly Sunni, alongside Protestant and Catholic minorities each around 3 percent, and smaller Hindu, Buddhist and Confucian populations recognized among the country's six officially sanctioned religions.
Hindu-Buddhist kingdoms, including Srivijaya and Majapahit, dominated the archipelago for over a millennium before Islam, spread gradually by traders and Sufi missionaries from the thirteenth century onward, became the majority faith across most islands by the sixteenth century; Bali alone retained a distinct Hindu majority, developing Balinese Hinduism, a form blending Indian Shaiva traditions with local ancestor and spirit veneration. Indonesian Islam is known for its historically syncretic and moderate character, absorbing earlier Hindu-Buddhist and animist elements especially in Javanese kebatinan mysticism, though the late twentieth century saw growing influence from more scripturalist reform movements, including Muhammadiyah and, on a more purist model, Salafi currents linked to Middle Eastern funding. Dutch colonial rule from the seventeenth century introduced Protestant Christianity in areas such as the Moluccas, Sulawesi and parts of Sumatra, while Catholic missions concentrated in Flores and Timor.