In the course of the 1990s the term social exclusion gained prominence in European social, urban, and housing policy. As opposed to the term 'poverty', social exclusion is not a quantitative but a relational concept. It is closely related with the term disadvantage. Because of the many different national contexts in which the term has been used, it can carry very different connotations. Sometimes it is equated with an urban underclass discourse, whereas in other contexts structural explanations are emphasised. In the field of housing, social exclusion has both a social and a spatial dimension. As far as the social dimension is concerned, social exclusion is equated with an undersupply of affordable housing or unmet housing need. On the spatial level, the social exclusion discourse has raised questions on the relationship between residence in certain localities and the experience of social disadvantage and marginalisation. © 2012