Research over the past few decades has highlighted the importance of social and emotional competence in preschool children on later academic, social, and psychological outcomes. Children who are socially and emotionally competent have increased socialization opportunities with peers, develop more friends, have better relationships with their parents and teachers, and enjoy more academic and social successes. Children who lack social and emotional competence are at risk for reduced socialization opportunities, rejection, withdrawal, behavioral disturbance, and achievement problems. Intervention programs that target social-emotional development in preschool are ideally situated to bolster these skills before the problems exacerbate. In this paper, research on the importance of social and emotional competence in young children is reviewed as it relates to immediate and long-term outcomes. Assessments of social and emotional development and behavioral adjustment are briefly reviewed, followed by a review of intervention programs with demonstrated empirical efficacy. Although preliminary evidence supports the utility of these intervention programs, additional research on short- and long-term efficacy is recommended, and more programs designed specifically for early childhood are needed. (Contains 2 tables.)