The goal of the present study was to investigate how the quality of the mother-child relationship, social self-concept, and the quality of peer relationships predict girls’ feelings of homesickness at a residential summer camp. We expected that children with secure attachments to their mothers, a more positive social self-concept, and better relationships with peers would report less homesickness at camp. Girls were 8 to 12 years of age. Mother-child attachment was assessed with a questionnaire and an interview completed prior to camp. Social self-concept was assessed with a questionnaire prior to camp, and peer relationships were assessed with questionnaires at camp. Peer relationships and social self-concept, but not mother-child attachment, were related to homesickness at camp. Social self-concept prior to camp and peer social support and friendship quality at camp predicted subsequent homesickness, whereas homesickness early in camp did not predict later assessments of peer relationships at camp. The findings suggest that social self-concept and relationships with peers may be protective factors for homesickness at summer camp.