Students who experience social withdrawal and anxiety (internalizing difficulties) are often overlooked in schools due to the covert nature of their symptoms. The literature lacks empirically supported preventive approaches for kindergarten students who are socially withdrawn and behind their peers in developing social skills. Furthermore, research suggests that parents often are not adequately involved in interventions during this critical period of social development. In response to this need, a school-based intervention was implemented to increase the positive social interaction of three kindergarten students on the playground. Treatment consisted of (a) social skills training, (b) adult mediation, (c) self-evaluation and reinforcement, and (d) parent involvement through home notes. The effects of this intervention were assessed on the playground during recess using partial interval recording of target students' positive interactions. During implementation of the intervention, all target students demonstrated improvements in social interaction. Future studies should investigate whether addressing the limitations of this study would yield stronger results with this underserved population.