The present investigation was designed to explore the relations between sport participation, peer acceptance, and global self-esteem. Peer acceptance was considered as a possible mediator of the relationship between sport participation and global self-esteem. The sample included girls (N=4,689) and boys (N=5,811) between the ages of 12 and 21 (M=15 years) who were part of the National Longitudinal Study of Adolescent Health. Analyses revealed that peer acceptance partially mediated the relation between sport participation and global self-esteem for girls as well as boys. Findings suggest the importance of considering how sport participation and self-evaluations in particular domains may contribute to global feelings of self-worth. The role of peers in this relationship is discussed in relation to changing social attitudes about girls' sport participation. © 2006 Springer Science+Business Media, LLC.