Sören Lüdeke examines transactional stress processing in friendly and romantic relationships among adolescents. He addresses, for the first time internationally, whether different adolescent behavioral problems explain variance in transactional stress processing in peer relationships within a model. One focus is on moderating protective and risk factors. In a control group design, 1,019 adolescents are studied using standardized instruments. Multivariate analyses demonstrate the significant explanatory value of behavioral problems for stress processing. In addition to predominantly socioeconomic risk factors, the study identifies prosocial behavior as a protective factor, particularly in hyperactive adolescents. The research highlights new perspectives on the social relationships of adolescents with behavioral problems.