Centuries of migration, mixed marriages, pirate raids, isolation and trade have produced a profusion of ethnic groups that has defied simple ethnic classification. There are at least 30 distinct ethnic indigenous groups in Sabah speaking different languages and close to 100 dialects.   The major races in Sabah are Kadazandusun, Bajau, Murut, Malay, and Chinese.

Sabah exhibits wide cultural diversity. Variation is found not only between cultures with different languages of the same family, but between those having related dialects. Indigenous belief systems recognise the Creator, spirits of the dead, demons and, especially in Dusunic societies, the rice spirit which was honoured in special celebrations after a bountiful harvest. Indigenous people generally believe Mount Kinabalu is the abode of the spirits of the dead. Traditional belief systems were linked to agricultural practices and management of the ecosystem.