Within primary schools teachers often group children according to certain criteria in order to facilitate teaching and learning. In particular teachers have been found to like grouping children according to level of attainment because of the ease of teaching in terms of differentiation, behaviour management and classroom management. However, existing research evidence is mixed on the benefits of such grouping strategy. This research looks at grouping children in the classroom by exploring children's self-perceptions of themselves as they relate to others (social comparison) within and across groups. Examining the social and emotional challenges for students in the context of the group provides insights into student wellbeing. The research was conducted within twelve English primary school Year 6/7 classrooms. Analysis of interview and survey data focused on how children felt and thought about themselves in relation to their peers within a classroom context. The guiding premise was to explore when, why and how students from different groups compare themselves and the impact this has on their self-evaluations and feelings of wellbeing. The findings suggest that, for devalued groups, comparison with others in the primary classroom perpetuate the inequalities and differences these students feel. Given pupils typically spend much of their time interacting with their peers within the classroom this raises questions about the formation of teaching groups and planning for pupil-pupil interaction.