This thesis explores the everyday practice of school bullying by examining children's participation in peer group activities as well as in school-based anti-bullying activities within an educational setting. The empirical material is drawn from a long-term (1 year) ethnographic study conducted among preadolescent children in a 5th grade class in a Swedish elementary school. An ethnomethodological approach is used in analysis of ethnographically based fieldnotes, and in detailed analysis of video recordings collected during participant observations.    The first study examines, through elaborated investigation of a peer group's everyday peer encounters, how social exclusion is situated within the flow of intricate, subtle and seemingly innocent interactions. In this, the study offers detailed information about how girls' everyday peer group interactions, taken across a range of activities, may be consequential for the process of social exclusion.    The second study examines the interactional moral work accomplished within the situated practice of ART classroom sessions on moral reasoning used as part of the school's anti-bullying prevention program. The study contributes an understanding of the interactional managment of children's moral stance-taking, something that has previously been overshadowed by the quest to project the outcomes for individual children's moral reasoning. The third study examines a gossip dispute event, in which a group of girls take action against another girl for reporting school bullying to the teacher. The study demonstrates how, as the gossip dispute unfolds, the girls accused of bullying appropriate and even subvert the social organization of the school's anti-bullying program, and manage to turn the tables so that the girl initially reporting to be a victim of bullying is cast as an instigator, and the girls accused of the bullying as victims of false accusations.    The thesis illuminates the complex meanings and functions of social actions referred to as bullying within a school context and in the literature. Also, it sheds light on the difficulties that come with teachers' attempts to structure children's social relationships. All in all, the thesis illuminates the need to challange an individualistic approach to bullying, recognizing the social and moral orders children orient to in their everyday life at school.