Peer aggression and victimization are currently of national concern due to their high association with maladjustment. Moreover, peer aggression and victimization can occur as different forms (overt, relational) and functions (proactive, reactive), which are usually not examined within the same model. Peer aggression and victimization within the school context can be the result of individually developed negative social cognitions. These negative cognitions, based within social information processing theory, include outcome expectancies and values for pain and suffering. In addition, positive cognitions such as perceived social competence can decrease adverse outcomes such as peer aggression and victimization. This project seeks to take previous research and expand upon it in two ways: 1) examine overt, relational, proactive, and reactive aggression and victimization as separate constructs, within the same model, in association with outcome values, expectancies, and perceived social competence; and 2) examine the potential of extracurricular activities to serve as a buffer between maladjusted cognitions and aggression and victimization. In addition, this study will examine if these relationships differ by activity type, age and gender. Participants included 371 middle and high school students. Findings point toward the importance of examining the separate functions of aggression and victimization, as outcome values and expectancies are associated specifically with higher levels of proactive aggression and victimization and reactive aggression. Activity participation, particularly activities that are not associated with the school that the participant attends, seems to be serving as a buffer against maladjusted cognitions and functions of aggression and victimization. Specifically, having high efficacy for activity participation (ability to meet expectations within activity) serves a buffer for both reactive aggression and reactive victimization. Activity participation benefits appear to not be present if the individual is only participating because their parents are forcing them to be there. No group differences were found. These findings serve to demonstrate the importance of establishing fit of activity context for youth as well as their motivation for participation. More broadly, it is important to examine functions of aggression and victimization in the same model as the forms of aggression and victimization. By better understanding the moderating role of activities, schools can potentially have a low cost intervention tool for peer aggression and victimization difficulties.