Adolescents and youth living with HIV have poorer antiretroviral treatment (ART) adherence and viral suppression outcomes than all other age groups. Effective interventions promoting adherence are urgently needed. We reviewed and synthesized recent literature on interventions to improve ART adherence among this vulnerable population. We focus on studies conducted in low- and middle-income countries (LMIC) where the adolescent and youth HIV burden is greatest. Articles published between September 2015 and January 2019 were identified through PubMed. Inclusion criteria were: [1] included participants ages 10-24 years; [2] assessed the efficacy of an intervention to improve ART adherence; [3] reported an ART adherence measurement or viral load; [4] conducted in a LMIC. Articles were reviewed for study population characteristics, intervention type, study design, outcomes measured, and intervention effect. Strength of each study's evidence was evaluated according to an adapted World Health Organization GRADE system. Articles meeting all inclusion criteria except being conducted in an LMIC were reviewed for results and potential transportability to a LMIC setting. Of 108 articles identified, 7 met criteria for inclusion. Three evaluated patient-level interventions and four evaluated health services interventions. Of the patient-level interventions, two were experimental designs and one was a retrospective cohort study. None of these interventions improved ART adherence or viral suppression. Of the four health services interventions, two targeted stable patients and reduced the amount of time spent in the clinic or grouped patients together for bi-monthly meetings, and two targeted patients newly diagnosed with HIV or not yet deemed clinically stable and augmented clinical care with home-based case-management. The two studies targeting stable patients used retrospective cohort designs and found that adolescents and youth were less likely to maintain viral suppression than children or adults. The two studies targeting patients not yet deemed clinically stable included one experimental and one retrospective cohort design and showed improved ART adherence and viral suppression outcomes. ART adherence and viral suppression outcomes remain a major challenge among adolescents and youth. Intensive home-based case management models of care hold promise for improving outcomes in this population and warrant further research.