Objectives <p>The peer context is crucial in victimization research, yet its role in repeat victimization remains understudied. This study examines the mediating pathways through which youth who are victimized increase delinquent peer affiliations, thereby elevating the risk of victimization later in life. Further, this study explores how this mediating mechanism changes over the life course as well as how the pathway varies by gender.</p> Methods <p>The analysis uses six waves of data from a longitudinal survey of South Korean youth aged 13–18. A Random-Intercept Cross-Lagged Panel Model (RI-CLPM) examines within-person changes over time to identify mediating mechanisms. In addition, to assess the gender-specific pathway of repeat victimization, a multi-group RI-CLPM is applied.</p> Results <p>Findings reveal that adolescents who are victimized increase delinquent peer affiliations, which in turn increase the risk of repeat victimization in later life. The mediating pathway operates during adolescence, but not at the beginning of emerging adulthood (age 18). In addition, for girls, this mechanism is more prominent earlier in development, while for boys, it is more evident later during adolescence.</p> Conclusions <p>These findings highlight the need for programs aimed at improving peer relationships after victimization, as well as targeted interventions, especially in the early stages of adolescence for girls and later stages for boys. The current study takes an important step toward a developmental and life-course perspective on victimization. Future research should continue to explore how peer contexts influence the cycle of victimization over time.</p>