This publication can be used by any individual or organization with a stake in developing or running a successful peer education program. The publication is divided into four main sections: 1. Peer Education Overview. This section defines peer education and its benefits, differentiates peer education from other peer-led approaches, discusses some of the challenges faced by program managers and other peer education advocates, and briefly explains how research findings can help improve programs. 2. Guidelines. This section provides evidence-based guidelines, developed by worldwide experts, on how to run a successful youth peer education program. This section features: Important cross-cutting issues that are relevant to all areas of a peer education program, evidence-based, practical guidelines and specific tips for implementing them, covering program planning, recruitment and retention of peer educators, training youth to be peer educators, leading peer education sessions, supervision and management, and monitoring and evaluation, boxes labeled "What the research tells us" that explain the available evidence on what works in peer education, boxes labeled "Example" that provide real-world examples of how the guidelines are used in successful programs. 3. Checklist and Action Planning Tool. This checklist can be used to plan a new peer education program or to assess the extent to which an existing program is implementing these guidelines. 4. Annexes. Annexes provide a comprehensive list of tools and publications on peer education, references used in the development of this publication, a sample code of conduct for peer education programs, a group exercise for organizations to use in their programs, and a glossary of key terms.