Indonesia: A Batak couple of northern Sumatra in traditional clothing, c. 1915.

Batak is a collective term used to identify a number of ethnic groups found in North Sumatra, Indonesia. The term is used to include the Toba, Karo, Pakpak, Simalungun, Angkola and Mandailing, each of which are distinct but related groups with distinct, albeit related, languages and customs (adat). Occasionally it is also used to include the Alas people of Central/Southern Aceh, but usually only as relates to language groups. In North Sumatra, Toba people typically assert their identity as 'Batak', while other 'Bataks' may explicitly reject that label, preferring instead to identify as specifically 'Simalungun', 'Karo', etc.