The phrase Orang Ulu means upriver people and is a term used to collectively describe the numerous tribes that live upriver in Sarawak's vast interior. Such groups include the major Kayan and Kenyah tribes, and the smaller neighbouring groups of the Kajang, Kejaman, Punan, Ukit, and Penan. Nowadays, the definition also includes the down-river tribes of the Lun Bawang, Lun Dayeh, Murut and Berawan as well as the plateau-dwelling Kelabits. The various Orang Ulu groups togther make up roughly 5.5% of Sarawak's population.

The Orang Ulu are artistic people with longhouses elaborately decorated with murals and woodcarvings. They are also well-known for their intricate beadwork detailed tattoos. The Orang Ulu tribe can also be identified by their unique music - distinctive sounds from their sape, a stringed instrument not unlike the mandolin.

A vast majority of the Orang Ulu tribe are Christians but old traditional religions are still practiced in some areas.