Relational aggression among early adolescents is a pervasive problem that negatively influences the health and well-being of youth. Strength-based approaches such as positive youth development (PYD) are a promising way to reduce risk of detrimental outcomes such as relational aggression. Participation in organized activities is a key way that youth build assets related to PYD. Yet, few researchers have examined empirically assets related to PYD as a mechanism by which organized activity participation may help reduce risk of relational aggression. In this study, we used structural equation modeling to investigate if assets associated with PYD mediate the relationship between organized activity participation and relational aggression using survey data from a diverse, school-based sample of early adolescents (N = 196; mean age = 12.39 years; SD = 0.52; 60% female; 45% African American, 27% White, 21% multiracial, and 7% other, 71% economically disadvantaged). We tested 2 competing models, 1 with decomposed PYD factors and 1 with an integrated PYD factor. Our results suggest that PYD better fit as an integrated versus decomposed construct, providing support for the notion that youth benefit most from assets related to PYD when they operate collectively. Our results also provide support for PYD-related factors as a mechanism by which participation may reduce risk of relational aggression. Limitations of this study, and implications for prevention are discussed.