African cities are under construction. Beyond the urban redevelopment schemes and large-scale infrastructure projects reconfiguring central city skylines, urban residents are putting their resources into finding land and building homes on city edges. The Suburban Frontier examines how self-built housing on the urban periphery has become central to middle-class formation and urban transformation in contemporary Tanzania. Drawing on original research in the city of Dar es Salaam, Claire Mercer details how the “suburban frontier” has become the place where Africa’s middle classes are shaped. As the first book-length analysis of Africa’s suburban middle class, The Suburban Frontier offers significant contributions to the study of urban social change in Africa and urbanization in the Global South.