Given the changing patterns of immigration in the Republic of Ireland in the past 10 years, this article considers how factors related to ethnic and gender identity mediate children's interaction with one another in a newly multi-ethnic Irish primary school. Central to the analysis is the exercise of power between children and how the experience of inclusion and exclusion in peer relations is underpinned by concepts of sameness/difference that draw upon wider discourses of ethnic and gender identity. Recommendations in relation to classroom and school practice are made with reference to the need for teachers to take account of the complexity of children's social worlds and the dynamics of power and control that operate within it.