A lot of literature on urban development in developing countries has entirely focused on the nexus between rapid urbanization, Gross Geographic Product (GGP), and poverty growth with little research that demonstrates what this impacts on urban sustainability, especially with increasing slums in rapidly urbanizing African countries. Available research has focused entirely on increasing the poverty level in urban Africa and its mitigation without a clear direction on what this means to slum improvement and urban sustainability. This paper aims to give a conceptual analysis that will help to understand the dynamics of urban sustainability and slum development. The historical perspectives and current realities of Kibera slums in Nairobi are reviewed.