This dissertation traces the evolution of immigration policy and practice in South Africa and Rhodesia/Zimbabwe from the Second World War to the 1970s. It outlines the importance of wartime experience in explaining the surge in post-war migration to southern Africa. It then traces the role of migration in the attempt to reinvent empire as Commonwealth in the decades after the Second World War as the British government encouraged migration to the Dominions and Southern Rhodesia despite a labor shortage. Using debates surrounding immigration, it highlights the tensions in South Africa and Southern Rhodesia as minority settler colonial regimes between gaining more white population and ensuring racial prestige in the 1940s and 1950s.Though always determined by race, by the 1960s, selective policies based on nationality and class gave way to more aggressive recruitment of immigrants defined by these states as white as a demographic defense of minority rule in a rapidly decolonizing continent. Though such efforts bore limited results in war torn Rhodesia, South Africa saw a dramatic increase of European and particularly British migration from the 1960s to the early 1980s. Alongside this political and demographic study, it uses migrant oral histories, biographies and letters to reveal the ongoing personal and familial ties between these nations and Britain, and the persistence of imperial migration networks even after the collapse of formal empire. Challenging the characterization of South African republic in 1961 and the Rhodesian Unilateral Declaration of Independence in 1965 as sharp breaks with the United Kingdom, this dissertation adds to a growing literature complicating the chronology of decolonization.