A retrospective cohort study was conducted among HIV-positive children and adolescents (&amp;lt;20 years old) who attended CTCs in seven hospitals in Tabora region from January 2018 to April 2022. Data were abstracted from CTCs’ database and patient records and this included socio-demographic, ART drug regimen, clinical, virological and immunological features, for a maximum of 52 months. Viral non-suppression was defined as plasma VL ≥1000 copies/mil after six months on ART, during the follow-up period. Cox proportional hazards regression model and Hazard ratios were used in estimating the determinants of viral non-suppression. 
