This paper explores the relations to Africa and African decolonisation of three key figures in Brazilian critical geographies and development studies, Manuel Correia de Andrade (1922-2007), Josué de Castro (1908-1973) and Milton Santos (1926-2001). Based on the analysis of their works and unpublished archives, my main argument is that the radical Third World perspectives that these intellectuals expressed anticipated later critiques to ideas of development as a neocolonial device. Drawing upon current literature on decolonisation, international conferencing and anti-racist solidarity networks, I discuss these matters in relation to these authors' interest in cultural diversity and internal colonialism. Crucially, they developed this sensitivity in the Brazilian Northeast, a region especially shaped by Afro-Brazilian and Indigenous cultural legacies. While supporting anti-imperialist nationalisms in the Third World, these Brazilian scholars fostered multilingual, internationalist and cosmopolite activism and scholarship. This is revealed by the study of the transnational networks that they developed during the exile and the various persecutions that many of them suffered after the 1964 military coup. I finally argue that these works can substantiate recent claims to 'decolonize' geography and development studies, at the condition that these fields of study take seriously their anti-imperial traditions and their 'voices from the South'.