Despite 50 years of promoting Bhinneka Tunggal Ika ("Unity in Diversity") as the official state motto, the concept of an "Indonesian" remains artificial and the country's citizens divide themselves along a vast slew of ethnicities, clans, tribes and even castes. If this wasn't enough, religious differences add a volatile ingredient to the mix and the vast gaps in wealth create a class society as well. Basically, the native Indonesians are of Malay stock. On a purely numerical scale, the largest ethnic groups are the Javanese (45%) of central and eastern Java, the Sundanese (14%) from western Java, the Madurese (7.5%) from the island of Madura, and Coastal Malays (7.5%), mostly from Sumatra. This leaves 26% for the Acehnese and Minangkabau of Sumatra, the Balinese, the Iban and Dayaks of Kalimantan, and a bewildering patchwork of groups in Nusa Tenggara and Papua — the official total is no less than 3000!

One particularly notable ethnic group found throughout the country is the Indonesian Chinese, known as Tionghoa or the somewhat derogatory Cina. At an estimated 6-7 million they make up just 3% of the population but continue to wield a disproportionate influence in the economy, with one famous — if largely discredited — study of companies on the Jakarta Stock Exchange concluding that as many as 70% of its companies (and, by extension, the country) were controlled by Chinese. They have thus been subject to persecution, with all Chinese forcibly relocated into urban areas in the 1960s, forced to adopt Indonesian names and bans imposed on teaching Chinese and displaying Chinese characters. Anti-Chinese pogroms have also take place, notably in the 1965-66 anti-Communist purges after Suharto's coup and again in 1998 after his downfall, when an estimated 1,500 Chinese were killed in riots in Jakarta. However, the post-Reformasi governments have overturned most of the discriminatory legislation, and Chinese writing and Chinese festivals have made a tentative reappearance.