Colonization (or colonisation) is a process of establishing foreign control over target territories or peoples for the purpose of cultivation, often by establishing colonies and possibly by settling them.

Colonization is sometimes used synonymously with settling, as with colonisation in biology, but while colonization historically involved settling, colonization through settling is the particular form called settler colonialism. Colonization is in this case structured and enforced by the settlers directly, while their, or their ancestors' metropolitan country maintains linkage or control through the settler's colonialism. Settler colonialization either rules as a minority group through oppression and assimilation the indigenous peoples, or by establishing them self as the demographic majority through driving away, disadvantaging or outright killing the indigenous people, as well as through immigration and births of metropolitan as well as other settlers.

European colonization of Australia, New Zealand, and other places in Oceania was fueled by explorers, and colonists often regarding the encountered landmasses as terra nullius ("empty land" in Latin). Resulting in laws and ideas such as Mexico's General Colonization Law and the United States' manifest destiny doctrine which furthered colonization.

Despite countless declarations and referendums from the United Nations on the independence of colonial countries and peoples, implemented since 1946, there are in the world still over 60 colonies – sometimes designated territories – including Puerto Rico, Guam, and Bermuda.