Social competence supports children's positive psychosocial development and is seen as a resource and protective factor. In contrast, deficits in social competences were found to be associated with psychological symptoms and disorders as well as peer problems. If we understand social competence as the ability to use social interactions to satisfy one's own goals and needs while at the same time considering the needs and goals of others, we can differentiate between two dimensions: self-oriented social skills, which are aimed at satisfying one's own needs (e.g., assertiveness and social participation), and other-oriented social skills, which are aimed at satisfying another's goals and needs (e.g., prosocial, cooperative, and nonaggressive behavior). Concepts such as the inner working models of the attachment theory, as well as schemata and scripts of sociocognitive models, give further theoretical notions we can rely on when investigating social competences. Common to these theoretical perspectives is the notion that children internalize important aspects of caregiving experiences, and that these mental structures influence children's emotional and behavioral responses to new social encounters. The present study investigated the predictive value of cognitive-emotional aspects such as social competence themes and narrative coherence in play narratives for behavioral ratings of social competence and peer relations in school-age children with and without psychiatric diagnoses. The sample consisted of 97 young people (aged 8-14 years) who were assessed at two time points (t1, t2). Children completed story stems on socioemotional conflicts of the MacArthur Story Stem Battery at t1. Story stem narratives were coded for social competence themes and narrative coherence. Parents answered standardized questionnaires on social competence, social problems, and peer relations of their children at t1 and t2. To assess psychiatric diagnoses, a structured diagnostic parent interview was conducted. Multivariate analyses, controlling for age, sex, and diagnostic status, showed that higher narrative coherence in play narratives was cross-sectionally and longitudinally associated with higher social competences, more positive peer relations, fewer social problems, and less social withdrawal, as rated by parents. Higher narrative coherence (but not social competence themes) was also predictive of an increase in positive peer relations and a decrease in social withdrawal 1.5 years later. The story stem method was originally developed for young children to assess children's representations in dealing with socioemotional conflicts. Our findings support the possibility of applying the method within a wider age spectrum, which is especially useful for longitudinal studies. Specifically, our results underline the importance of narrative coherence for children's socioemotional development and its clinical value.