IntroductionGlobally, an estimated 30% of new HIV infections occur among adolescents (15–24 years), most of whom reside in sub-Saharan Africa. Moreover, HIV-related mortality increased by 50% between 2005 and 2012 for adolescents 10–19 years while it decreased by 30% for all other age groups. Efforts to achieve and maintain optimal adherence to antiretroviral therapy are essential to ensuring viral suppression, good long-term health outcomes, and survival for young people. Evidence-based strategies to improve adherence among adolescents living with HIV are therefore a critical part of the response to the epidemic.MethodsWe conducted a systematic review of the peer-reviewed and grey literature published between 2010 and 2015 to identify interventions designed to improve antiretroviral adherence among adults and adolescents in low- and middle-income countries. We systematically searched PubMed, Web of Science, Popline, the AIDSFree Resource Library, and the USAID Development Experience Clearinghouse to identify relevant publications and used the NIH NHLBI Quality Assessment Tools to assess the quality and risk of bias of each study.Results and discussionWe identified 52 peer-reviewed journal articles describing 51 distinct interventions out of a total of 13,429 potentially relevant publications. Forty-three interventions were conducted among adults, six included adults and adolescents, and two were conducted among adolescents only. All studies were conducted in low- and middle-income countries, most of these (n = 32) in sub-Saharan Africa. Individual or group adherence counseling (n = 12), mobile health (mHealth) interventions (n = 13), and community- and home-based care (n = 12) were the most common types of interventions reported. Methodological challenges plagued many studies, limiting the strength of the available evidence. However, task shifting, community-based adherence support, mHealth platforms, and group adherence counseling emerged as strategies used in adult populations that show promise for adaptation and testing among adolescents.ConclusionsDespite the sizeable body of evidence for adults, few studies were high quality and no single intervention strategy stood out as definitively warranting adaptation for adolescents. Among adolescents, current evidence is both sparse and lacking in its quality. These findings highlight a pressing need to develop and test targeted intervention strategies to improve adherence among this high-priority population.