Consistent research shows that peer victimization predicts internalizing symptoms in childhood and adolescence, but the extent to which peer victimization and its harmful effects on mental health persists into young adulthood is unclear. The current study describes patterns of physical and relational victimization during and after high school, and examines concurrent and prospective associations between internalizing symptoms (depressive and anxious symptoms) and peer victimization (physical and relational) from adolescence to young adulthood (ages 12–27). Data were collected from the Victoria Healthy Youth Survey, a five-wave multicohort study conducted biennially between 2003 and 2011 ( N = 662). Physical victimization was consistently low and stable over time. Relational victimization increased for males after high school. Both types of victimization were associated concurrently with internalizing symptoms across young adulthood for males and for females. Although sex differences were important, victimization in high school also predicted increases in internalizing problems over time.