Research Findings: This study aimed to investigate the developmental path of social skills in early childhood, the associated predictors, and its impact on later school performance. This prospective longitudinal study included 2,121 children, ages 3-5 at baseline, from the general population in a mid-sized Swedish municipality. Results show both stability and change in social skills. Stable low social skills increased the risk for poor school performance, while stable high social skills increased the chance for good school performance in primary school. With some notable gender differences, both individual and family factors were significant predictors of stable low and stable high paths of social skills during early childhood. Practice or Policy: Whether the goal is to improve children's social skills or their performance in school, this study provides important clues for prevention. We identified several potential targets for interventions to promote early social skills development, which may in turn promote positive school performance. It is also notable that there seem to be gender differences in which factors are important, indicating the need for gender-differentiated interventions.