Countries across Africa are rapidly transitioning from rural to urban societies. The UN projects that 60% of people living in Africa will be in urban areas by 2050, with the urban population on the continent tripling over the next 50 years. The challenge of building inclusive and sustainable cities in the context of rapid urbanization is arguably the critical development issue of the 21st Century and creating food secure cities is key to promoting health, prosperity, equity, and ecological sustainability. The expansion of Africa’s urban population is taking place largely in secondary cities: these are broadly defined as cities with fewer than half a million people that are not national political or economic hubs. The implications of secondary urbanization have recently been described by the Cities Alliance as “a real knowledge gap”, requiring much additional research not least because its patterns of migration and settlement challenge conventional understandings of urbanism and conventional approaches to municipal governance. This collection focuses on the intersection between rapid secondary urbanization, food system transformation and food security through (a) discussion of the nature of food system transformation in secondary African urban centres and whether this process is similar to or diverges from the better-documented changes in primary cities; and (b) empirical case studies of food system transformation, food security outcomes and the nutrition transition in different national and local contexts.