This study examined the effect of close relationships (best friendship and romantic relationship) on late adolescents' casual attributions for peer victimization. A total of 1106 twelfth grade students completed self-report measures of perceived peer victimization, self-blame attribution, psychological maladjustment (loneliness and social anxiety), and quality of close peer relationships. Results indicated that self-blame partly mediated the link between peer victimization and psychological maladjustment. Relationship quality moderated the victimization-self-blame relation. Participants were more likely to endorse self-blame attributions for peer victimization when they had a negative relationship with a best friend or romantic partner. The moderated effect of negative best friendship quality was only significant for girls, whereas the moderated effect of negative romantic relationship quality was only significant for boys. Implications of these findings for future research on close relations during adolescence and for interventions to reduce the effects of peer victimization were discussed. (Contains 2 figures and 5 tables.)