The term indigenous peoples has no universal, standard or fixed definition, but can be used about any ethnic group who inhabit the geographic region with which they have the earliest historical connection. However, several widely-accepted formulations, which define the term "Indigenous peoples" in stricter terms, have been put forward by prominent and internationally-recognized organizations, such as the United Nations, the International Labour Organization and the World Bank. Indigenous peoples in this article is used in such a narrower sense.

Drawing on these, a contemporary working definition of "indigenous peoples" for certain purposes has criteria which would seek to include cultural groups (and their continuity or association with a given region, or parts of a region, and who formerly or currently inhabit the region either:

• before its subsequent colonization or annexation; or
• alongside other cultural groups during the formation of a nation-state; or
• independently or largely isolated from the influence of the claimed governance by a nation-state,

To the above, a criterion is usually added to also include:

• peoples who are self-identified as indigenous, and/or those recognised as such by other groups.

Note that even if all the above criteria are fulfilled, some people may either not consider themselves as indigenous or may not be considered as indigenous by governments, organizations or scholars.

Other related terms for indigenous peoples include aborigines, aboriginal peoples, native peoples, first peoples, first nations and autochthonous (this last term having a derivation from Greek, meaning "sprung from the earth"). Indigenous peoples may often be used in preference to these or other terms, as a neutral replacement where these terms may have taken on negative or pejorative connotations by their prior association and use. It is the preferred term in use by the United Nations and its subsidiary organizations.