OBJECTIVE: We are failing to reach 95-95-95 for adolescents living with HIV (ALHIV). Sexual abuse and intimate partner violence (IPV) may impact antiretroviral therapy (ART) adherence, with high rates of 17.4 and 29.7%, respectively, across the southern sub-Saharan African region. However, evidence on their associations with adolescent ART adherence remains limited, with only three cross-sectional studies globally. DESIGN: A prospective cohort of ALHIV (sample N = 980, 55% female individuals, baseline mean age 13.6 years) were recruited from 53 health facilities in South Africa's Eastern Cape Province and responded to a structured questionnaire at 18-month and 36-month follow-up (2015-2016, 2017-2018). METHODS: A repeated-measures random effects model assessed multivariable associations of self-reported sexual abuse and IPV with past-week ART adherence, controlling for individual, socioeconomic, and HIV-related factors. Past-week adherence was defined based on currently taking ART and not having missed any doses in the past 7 days (including weekends). We further fitted a moderation model by sex. RESULTS: Fifty-one percent of adolescents reported consistent ART adherence at both time points. Exposure to IPV was associated with lower odds of self-reported ART adherence (aOR 0.39, 95% CI 0.21-0.72, P = 0.003), as was sexual abuse (aOR 0.54, 95% CI 0.29-0.99, P = 0.048). The marginal predicted probability of ART adherence for adolescents with no exposure to either IPV or sexual abuse was 72% (95% CI 70-74%) compared with 38% (95% CI 20-56%) for adolescents with exposure to both IPV and sexual abuse. Moderation results showed similar associations between sexual violence and ART adherence by sex. CONCLUSION: Sexual violence prevention and postviolence care may be essential components of supporting adolescent ART adherence. Integration of HIV and violence prevention services will require accessible services and simple referral systems.