There has been a high rate of urbanization and influx of people into the Central Business District (CBD) and inner city of Johannesburg, South Africa over the last thirty years. One of the consequences of this rapid urbanization is a severe housing shortage, especially for lower income individuals. Investors and developers need to have a sound business case when making any investment in real estate; more so when the target market is tenants seeking affordable housing as these tenants are extremely sensitive to rentals that do not fall within a certain range. One of the questions that arise is what factors encourage or discourage private sector investment into affordable housing in a large city like Johannesburg in a developing country like South Africa.Various developers, property managers and asset managers were surveyed to assess their views regarding the factors that encourage or discourage private sector investment into affordable housing in Johannesburg.The purpose of this paper is to:•Consider the relevant literature, in an international context, regarding the factors that encourage private sector investment in the inner cities of major cities, especially in developing countries; •Consider what factors are specifically relevant in Johannesburg;•Share the results of research conducted with various developers, property managers and asset managers; and•Suggest what factors will encourage private sector investment in the inner city of not only Johannesburg, but also other major cities in South Africa, as well as other developing countries and whether or not these differ from the factors identified in the international literature.