National statistics on school exclusions published annually by the Scottish Executive indicate the over-representation of particular groups within the whole group of those excluded. Official and policy accounts of school exclusion were explored and tensions found between social policy constructions of exclusion and school policy. The latter was rooted in understandings of challenging behaviour as an additional support need or as a problem of school functioning. Not only were these discourses in tension with each other, resulting in inconsistencies in practice, but both ignored the social and cultural factors structuring school exclusion statistics. In the first empirical phase of the research, key informant interviews were used to probe professional and personal experience of exclusion, to contrast these with official views, and to inform the main phase of the investigation. The second, main phase of the research used a case-study sample of twenty excluded pupils, in four secondary schools, to investigate inequitable patterns of exclusion. Data was gathered from classroom observation, from school documentation and from interviews with pupils, parents and school staff. The main focus of the enquiry was the social identities of excluded pupils. Gender was a main category of analysis in this research, and especially masculine identities since boys were so predominant in exclusion statistics. The thesis argues that school exclusions are not just an indicator of wider social exclusion but an effect of policy which pursues social justice without fair distribution of social and economic benefits. Structural inequality has ensured that children and families are differently positioned to schooling and has limited the scope of schools in fostering engagement with schooling. Increased participation particularly in curriculum planning, is nevertheless a worthwhile and realistic aim for schools seeking to minimize school exclusion.