The population of Indonesia according to the 2010 national census is 237.6 million, with 58% living on the island of Java, the world's most populous island.

Despite a fairly effective family planning program that has been in place since the 1960s, the population is expected to grow to around 254 million by 2020 and 288 million by 2050, falling to sixth behind Pakistan and Brazil sometime before 2050.

Indonesia includes numerous ethnic, cultural and linguistic groups, some of which are related to each other. Since independence, Indonesian (a form of Malay and official national language) is the language of most written communication, education, government, and business. Many local ethnic languages are the first language of most Indonesians and still important.