Informal urban settlements have a major influence on the well-being of a large section of global humanity. Yet there has been very little research on their role in facilitating social mobility. In theory such settlements may foster human progress by linking rural-urban migrants to the services, contacts and livelihoods concentrated in cities. The paper uses longitudinal data for South Africa to explore the magnitude of social progression among people living within informal settlements compared with the residents of rural areas and formal urban areas. It finds that there may be some advantage from living in an informal settlement compared with a rural area, but the effect is not strong. The impact may be more substantial in the more prosperous Gauteng city-region than in other urban regions.