ABSTRACT Despite the major advances in the treatment of human immunodeficiency virus (HIV) and HIV-associated comorbidities, the adoption of newer regimens in children has fallen far behind that in adults. Consequently, health outcomes of children living with HIV (CLWH) is worse than in adults. Of the CLWH receiving antiretroviral therapy (ART) in 2022, 81% had a suppressed viral load, compared with 93% of adults aged 15 years or older. In the same year, children under 15 years old accounted for only 4% of all people living with HIV (PLWH), but they accounted for 13% of all AIDS-related deaths. For decades, children were forced to use adult formulations or poorly tolerated pediatric formulations with unacceptable properties (palatability, pill size, pill burden, high dosing frequency), high toxicity profiles and low genetic barrier to resistance. Dolutegravir (DTG) is a novel second-generation integrase strand transfer inhibitor (INSTI) that is highly efficacious, safer and easy to use with a higher genetic barrier to the emergence of HIV drug resistance. While DTG is a potential game changer for children, the accelerated rollout of DTG-based ART in children in low- and middle- income countries (LMICs) occurred in the setting of limited research data in pediatric populations. Currently, fundamental questions remain about the adequacy of the weight-band dosing of the generic pediatric DTG scored 10 mg dispersible tablet, drug-drug interactions in the setting of treatment of latent and active tuberculosis (TB) and overall long-term effectiveness of DTG-based ART in children. The goal of this application is to address fundamental research gaps to assure optimal use of DTG in children and adolescents in real-world settings. The following specific aims will be pursued: 1) To evaluate the pharmacokinetics and safety of the generic pediatric dolutegravir 10 mg scored tablet in children with HIV with and with TB coinfection weighing less than 20 kg. 2) To examine the pharmacokinetics and safety of weekly isoniazid and rifapentine (3HP) in children and adolescents and the drug-drug interactions with dolutegravir in those with HIV infection. 3) To examine the longitudinal adherence, virologic response and changes in body mass index, lipid, glycemia, renal, and hepatic profiles in children and adolescents with HIV on DTG-based ART. The results of this project would provide real-world data that has the potential to impact HIV treatment guidelines for children and adolescents.