The Doctrine of Discovery is a principle in public international law that arose when European nations discovered non-European lands and acquired special rights, such as property and sovereignty rights, on those lands. The Doctrine of Discovery was first articulated as a legal formulation in the U.S. Supreme Court case Johnson v. MIntosh in 1823. In Marshalls formulation of the doctrine, discovery of territory previously unknown to Europeans gave the discovering nation title to that territory against all other European nations, and this title could be perfected by possession. The Doctrine of Discovery provided a framework for Christian explorers, in the name of their sovereign, to lay claim to territories uninhabited by Christians. The Doctrine of Discovery established a religious, political, and legal justification for colonization and seizure of land not inhabited by Christians.

The Doctrine of Discovery has been condemned as socially unjust, racist, and in violation of basic and fundamental human rights. The United Nations Permanent Forum on Indigenous Issues (UNPFII) noted the doctrine of discovery "as the foundation of the violation of their (Indigenous people) human rights". The Doctrine of Discovery was used to legitimize the colonization of lands outside of Europe and to justify the taking of Native peoples’ land in what became the United States. The Doctrine of Discovery became the basis of all European claims in the Americas as well as the foundation for the United States’ westward expansion.

Today, the Doctrine of Discovery is still mentioned in American Imperialism and in regards to the treatment of indigenous people. The Catholic Church officially repudiated the Doctrine of Discovery in 2023.