A growing number of international studies document the importance of regular school attendance. There is a consensus among authors that absenteeism has negative implications for academic achievement as well as the social development of the child and may put them at a disadvantage in terms of their position in the education and labour market. Most of the existing studies have focused on school absenteeism among adolescents with studies on poor school attendance among young children relatively rare. This paper addresses this gap in research by exploring factors that are related to school absenteeism in Irish primary schools. Drawing on a nationally representative study of nine-year-olds, it demonstrates the complexity of the issue. The findings indicate that a combination of institutional and individual factors shape patterns of poor school attendance in Irish primary schools. While the data relate to the Irish situation, the paper raises a number of issues of interest to an international audience.