The link between the experience of peer victimization (PV) and future psychological maladjustment has been consistently documented; however, little is known about intermediary cognitive processes that underlie this relation or how these processes vary across childhood. The present study examined the prospective relations between physical and relational PV and the development of negative and positive automatic thoughts and self-cognitions. Self-reports of cognitions and peer nomination measures of victimization were obtained from 1,242 children and young adolescents (Grades 3 through 6) in a two-wave longitudinal study. The results revealed that PV predicted significant increases in negative views of the self, world, and future and decreases in self-perceived competence for girls under 11 years of age, with the effect being stronger for younger girls. PV was not significantly associated with changes in positive or negative self-cognitions for older girls or for boys of any age. These findings support the hypothesis that PV may be linked to future psychopathology through its influence on self-cognitions, but only for girls.