Christianity is Indonesia's second-largest religion, after Islam. As of 2023, Christians constitute 10.5% (29.4 million) of the country's population, with 7.4% Protestant (20.8 million) and 3.0% Catholic (8.6 million). In Indonesia, the word Kristen (lit. 'Christian') exclusively refers to Protestants, while Catholics are referred to as Katolik. Some provinces in Indonesia are majority Christian. In the 21st century, the rate of growth and spread of Christianity has increased.
Indonesia has the second-largest Christian population in Southeast Asia after the Philippines, the largest Protestant population in Southeast Asia, and the third-largest Christian population in Asia after the Philippines and China. Indonesia also has the second-largest Christian population in the Muslim world after Nigeria.