We assessed clinical outcomes among children, adolescents and young people (< 25 years) on darunavir-based antiretroviral therapy (ART) in nine sub-Saharan African countries. Third-line ART centers in Cameroon, Eswatini, Kenya, Lesotho, Nigeria, Rwanda, Uganda, Zambia and Zimbabwe. From January 2019 to December 2022, we collected data from a cohort of children, adolescents and young people receiving third-line ART from 9 sub-Saharan African countries. Data on treatment continuity, viral suppression, death and clinic transfers were extracted from medical records and summarized. Cox proportional hazards models were used to identify factors independently associated with retention in care. Of 871 participants enrolled, median age 14.8 (range: 0.2 - 24.7) years, 488 (56.0%) male; 809 (92.9%) [median duration of follow-up of 28.3 months (IQR:17.5 - 45.2)] had final outcomes after initiating third-line ART. Of these, 711 (87.9%) were alive and in care at the end of study follow-up, 29 (3.6%) died, 30 (3.7%) transferred to other facilities, and 39 (4.8%) were lost to follow-up. Retention in care was less likely among males compared to females (aHR: 0.85, 95%CI 0.72-1.0), and in 10-14-year-olds compared to younger children. Adolescents (15-19 years) had higher mortality compared to children <10 years of age (aSHR: 4.20, 95% CI 1.37-12.87). Viral suppression was seen in 345/433 (79.7%), 249/320 (77.8%), and 546/674 (81.0%) patients with results at 6, 12 months and study end, respectively. A high proportion of children and young people receiving third-line ART in Sub-Saharan Africa, remain in care, and attain viral suppression during follow-up.