In an effort to increase students' success, schools and communities have begun to develop school-based mentoring programs (SBMP) to foster positive outcomes for children and adolescents. However, experts have called for more research into the effectiveness of these efforts for students across grade levels. Therefore, this study was designed to examine the impact of participation in a SBMP on behavioral and social outcomes for sixth through tenth grade students. Analyses revealed that compared to control students, SBMP participants had significantly fewer unexcused absences (with moderate effect size) and discipline referrals (with large effect size) and reported significantly higher scores on four measures of connectedness (with moderate to negligible effect sizes). First year participants also reported significantly higher scores on one measure of connectedness (with a large effect size). Implications for practice and suggestions for further research are provided.