The purpose of this research study was to examine the effectiveness of training students in peer mediation (Mediator Mentors Curriculum), and how peer mediation-training influences third- through fifth-grade student perceptions of self-esteem, resiliency, and social competence. The research was a mixed-methods design with both quantitative and qualitative data analysis. The instrumentation included student surveys, teacher focus group interviews, as well as individual interviews with school principals. There were three research questions that focused on the following areas of peer mediation training: student perceptions of self-esteem, resiliency, social competence and conflict resolution skills; the differences among students who are taught peer mediation skills and those who are not; reported conflicts between groups; and other factors. The findings revealed that students demonstrated higher levels of social competence as a result of receiving peer mediation training, but lower levels of self-esteem and resiliency. Mediators were inclined to implement effective conflict resolution skills, while nonmediators did not. The hope was that results of this study will contribute to the garnering of peer mediation programs in schools, and determine if peer mediation programs should be encouraged as interventions in schools for improved self-esteem and social competence among students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]