'Apayao' most likely originates from an indigenous language of northern Luzon associated with the local Isnag/Isneg people; the exact original form and meaning are uncertain.

'Apayao' has been used historically as a place and tribal name in northern Luzon. Administratively, the name appeared in the combined province 'Kalinga-Apayao' (a former province) and later became the official name of the separate province 'Apayao' after the split from Kalinga in 1995.

Originally a local place or tribal name referring to the people or locality, the term's primary modern use is as the official name of a Philippine province.