The goal of this compendium is to answer critical questions that move forward USAID’s mission of supporting (a) the adoption of evidence-based practices in adolescent- and youth-friendly HIV care and services to help at-risk adolescents (ages 10–19 years) and youth (ages 15–24 years) stay HIV-free, and (b) the provision of comprehensive packages of HIV prevention, care, treatment, and retention services to adolescents and youth living with HIV in order to promote their successful transition to adulthood.