Resumen: Recognizing aggressive behavior at an early age is vital to identify problematic trajectories that may increase the risk of behavioral and social adaptation problems at school and during adolescence. This requires scales capable of measuring this behavior. In this study, the Scale of Preschool Social Behavior (psbs) - Teacher Form was validated using a Confirmatory Factor Analysis (cfa) in a national context. We used a sample of 538 children and 12 educators from 4 kindergartens and 5 public schools in Santiago, Chile. The results revealed two main factors: aggression and pro-social behavior, similar to the original scale. This study contributes to the early detection of physical and relational aggression in the preschool stage through the development of reliable measurements that guide prevention programs.