The preschool stage represents a critical period for the development of skills that support successful adjustment in later stages of life. In particular, strong social competence serves as a protective factor against the emergence of childhood problems. As a result, increasing attention has been given to the development and implementation of preventive programs. In recent years, there has been a notable rise in emotional and behavioral difficulties among young children, which has led to the creation of various national and international prevention initiatives. To consolidate the existing evidence, this study conducted a systematic review of group-based social skills prevention programs targeting preschool-aged children (0-7 years). Searches were carried out across several databases, including APA PsycINFO, Web of Science, MEDLINE (PubMed), SCOPUS, PSICODOC, and ERIC. From an initial pool of 10,600 records, 33 articles met all inclusion criteria. The selected programs varied in terms of methodology, study design, duration, and number of sessions. Overall, findings indicated that most children showed improvements in social skills as well as reductions in emotional and behavioral problems. These results support the effectiveness of school-based social skills training as a preventive strategy during early childhood. Practically, the findings underscore the relevance of incorporating evidence-based social skills programs into preschool curricula to support children's socio-emotional development and prevent future psychological difficulties.