Population transfer is the movement of a large group of people from one region to another by state policy or international authority, most frequently on the basis of ethnicity or religion. Banishment or exile is a similar process, but is forcibly applied to individuals and groups.

Often the affected population is transferred by force to a distant region, perhaps not suited to their way of life, causing them substantial harm. In addition, the loss of all immovable property and, when rushed, the loss of substantial amounts of movable property, is implied.

Population exchange is the transfer of two populations in opposite directions at about the same time. Such exchanges have taken place several times in the 20th century, such as during the partition of India and Pakistan and between post-Ottoman Turkey and Greece.

According to political scientist Norman Finkelstein transfer was considered as an acceptable solution to the problems of ethnic conflict, up until around World War II and even a little afterward, in certain cases. Transfer was considered a drastic but "often necessary" means to end an ethnic conflict or ethnic civil war. The feasibility of population transfer was hugely increased by the creation of railroad networks from the mid-19th century.