By exploring country programs and interventions in youth-friendly harm reduction service provisions, this guide offers a practical approach to designing and implementing such services in Nigeria. This guide is suitable for three audiences: the reader who may not be abreast of harm reduction services in Nigeria, organizations that advocate for better harm reduction policies, and the experienced personnel who would find this guide helpful in uncovering insights and patterns when implementing harm reduction services for young people. This project was implemented with the support of the Global Fund Community Engagement Strategic Initiative.