Peer education programs in higher education conduct peer educator training; however, there is minimal empirical evidence supporting the structure and evaluation of peer educator training. The problem addressed by the present study was the inconsistencies in and scant assessment of university peer educator training and implementation. Ineffective peer educator training could adversely impact student learning, peer educator development, program effectiveness, and institutional retention numbers. The purpose of the study was to understand peer education coordinators' implementation and assessment of training for university peer educators in the United States. The guiding theoretical framework for the study was the sociocultural theory. The qualitative multiple case study recruited 12 peer education coordinators through two listservs for learning assistance programs. The study used a semi-structured interview guide and collected training materials to answer three research questions associated with (1) how peer education coordinators serve as more knowledgeable others, (2) assessment of peer educator training, and (3) utilization of the zone of proximal development. Analysis included thematic analysis with coding of interview and document data. The findings suggested that peer education coordinators facilitate and develop peer educator training, conduct informal and formal assessments, and use the components of the zone of proximal development during peer educator training. The potential implications include the need to develop best practices for implementing and assessing peer educator training to ensure peer educators are being trained effectively. Suggestions for future practice involve implementing formal assessments for veteran peer educators, aligning observations with training, and administering pre- and post-assessments. Future research should expand on the effectiveness of formal assessment, commonality of training topics, baseline knowledge of peer educators, and the peer education coordinator's role across campus. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]