Objectives: To evaluate a paediatric treatment-support intervention for home-based treatment of HIV infection or tuberculous meningitis (TBM). Methods: A randomised-controlled study comparing local standard care (controls) with standard care plus intervention (combining adherence education, reinforcement and monitoring) in children aged 0–14 years. We recorded adherence measures (self-report, pill-count, drug-assays for isoniazid and rifampicin in urine and pyrazinamide in saliva), difficulties administering medication and PedsQL™questionnaires for health-related quality-of-life (HRQoL) and family impact. Results: In the HIV group (6-months follow-up, n = 195), more children had above-median HRQoL-scores in the intervention group than in the control group (P = 0.009). Problems reported administering medication declined between baseline and follow-up for controls (P = 0.043). Disclosure of HIV status to the child increased between baseline and follow-up in both groups (intervention P < 0.001; control P = 0.031). In the TBM group (3-months follow-up, n = 43), all adherence measures remained high for both intervention and controls, except for rifampicin which declined between baseline and follow-up in the intervention group (P = 0.031). The intervention group maintained above median HRQoL-scores between baseline and follow-up, when the number of children with above-median HRQoL-scores decreased in the controls (P = 0.063). More children in the intervention group had above-median family impact-scores than controls (P = 0.040). Conclusions: The low-cost, culturally friendly treatment-support intervention had beneficial effects on health-related quality of life, family impact, caregiver disclosure of HIV status to the child, increased caregiver reporting of medication non-adherence and caregiver reporting of difficulties administering medication. Treatment adherence was not significantly affected in either HIV or TBM group.