This paper critically examines the capacity of sport-based intervention programmes to engender social mobility of disadvantaged young people. The paper draws on a mixed-methods study of the Vencer programme in Rio de Janeiro, Brazil, to analyse the development opportunities created by the programme as well as the constraints faced by participants in seeking to convert these opportunities into occupational attainment and social mobility. It is concluded that participants’ prospects and possibilities for upward social mobility are strongly affected by structural factors emanating from the labour market and education system. Moreover, where social mobility does take place it is at a personal level rather than at any structural level. Directions for future research into social mobility through sport are proposed.