Early adolescence is a critical time for promoting emerging adolescents' positive social skill development and mental well-being. This investigation addresses unique characteristics of these relations by holistically examining how school-based social cohesion and school stress combine to impact peer aggression and prosocial behavior. Using a person-centered approach, fifth and sixth grade students (N = 142, M = 10.68 years) were assessed on measures of social cohesion, school stress, peer aggression, and prosocial behavior at fall and spring time points. Latent cluster analyses revealed three student profiles: (1) low cohesion and high stress, (2) high cohesion and low stress, and (3) medium cohesion and medium stress. Significant differences in peer aggression and prosocial behavior were found between the three profiles and follow-up analyses examine profiles in association with other domain stress. Findings are discussed with respect to how schools may enhance services to promote prosocial behavior and mitigate aggressive trajectories.