The Dayak or Dyak are native people of Borneo. 'Dayak' is a loose term for over 200 riverine and hill-dwelling ethnic subgroups; located principally in the interior of Borneo; each with its own dialect; customs; laws; territory and culture; although common distinguishing traits are readily identifiable.

Dayak languages are categorised as part of the Austronesian languages in Asia. The Dayak were animist in belief; however many converted to Christianity; and some embraced Islam more recently. Estimates for the Dayak population range from 2 to 4 million.