This paper argues that the primary value-added of a a social exclusion perspective for development policy lies not so much in the ‘naming’ of a new problem, as it appears to have done in northern social policy studies, but in offering an integrated way of looking at different forms of disadvantage which have tended to be dealt separately in the development studies literature. In particular, it captures the experience of the certain groups and categories in a society of being somehow ‘set apart’ from others, of being ‘locked-out’ or ‘left behind’ in a way that the existing frameworks for poverty analysis had failed to capture. Consequently, it has insights to offer such analysis beyond those offered by these frameworks. It also allows a bridge between the concept of poverty, which focuses on absolute levels of deprivation, and that of inequality, which is concerned with distributional issues. Social exclusion helps to highlight inequalities in the distribution of deprivation of the poor. The paper is in three parts: a conceptualisation of social exclusion, the empirical exploration of its relevance to the key MDGS related to poverty, health and education, and the policy implications for linking poverty reduction strategies to the challenge of building more inclusive societies.