In a short-term longitudinal study of 432 first-grade children, we examined whether gender interacted with contextual differences (school-level poverty) and individual differences at school entry (behavioral problems, emotional problems, and social competence) to predict changes in peer physical and relational victimization and receipt of prosocial acts. Gender differences in peer victimization were observed in schools with low levels of student poverty, such that girls showed significant decreases in peer victimization relative to boys. Girls in schools with high levels of student poverty were at greater risk for increases in victimization relative to girls in low-poverty schools. Individual differences at school entry also contributed to risks for physical (but not relational) victimization. Girls with high levels of behavioral problems and boys with low levels of social competence showed increased risks for physical victimization. We discussed the implications of the present findings for school-based peer-victimization prevention programs.