© 2015, Annals of Family Medicine, Inc. All rights reserved. SUBSTANTIAL evidence documents the benefits of peer support provided by community health workers, lay health advisors, promotores de salud, and others. The papers in this supplement, all supported by the Peers for Progress program of the American Academy of Family Physicians Foundation, contribute to the growing body of literature addressing the efficacy, effectiveness, feasibility, reach, sustainability, and adoption of peer support for diabetes self-management. They and additional papers supported by Peers for Progress contribute to understanding how peer support can be implemented in real world settings. Topics include examination of the peers who provide peer support, reaching the hardly reached, success factors in peer support interventions, proactive approaches, attention to emotions, peer support in behavioral health, dissemination models and their application in China, peer support in the patient-centered medical home, research challenges, and policy implications.