**Background:** Antiretroviral therapy (ART) is the largest public-sector health investment in sub-Saharan Africa (SSA), with over US$12.1 billion invested in 2021 and over 20 million people on ART. While the direct benefits for treated individuals are well-documented, the broader societal effects on household and family members—termed 'spillover effects'—remain poorly understood. This scoping review systematically examines intergenerational spillover effects of ART provided to working-age adults (18–65 years) on children (downward) and older adults (upward) in SSA.
**Methods:** A systematic scoping review was conducted between March and April 2022 following the Arksey and O'Malley framework. Nine databases were searched: PubMed, PsycINFO, EconLit, OTseeker, AIDSInfo, Web of Science, CINHAL, Google Scholar, and African Index Medicus. Conference abstracts, grey literature, and reference lists were also screened. Inclusion criteria were empirical studies (quantitative or qualitative) reporting outcomes of individuals who coreside or are affiliated with a person living with HIV on ART in SSA. Studies on vertical HIV transmission prevention were excluded. The search yielded 5,623 articles; after screening, 26 studies were included (21 from databases/registers, 5 from citation searching/expert consultation). Study characteristics were extracted, and spillover effects were categorised by direction (downward, upward, not specified) and type (wealth/labour, health/healthcare utilisation, food security/nutrition, schooling, caregiving, coresidence/relationships).
**Key Results:** The 26 studies were published between 2005 and 2022, averaging approximately 1.5 studies per year. Most studies were quantitative (21/26), with longitudinal/cohort (9 studies) and quasi-experimental (9 studies) designs being most common. Single-country studies were concentrated in Uganda (9), South Africa (5), Kenya (3), and Zambia (3); no studies were identified from high-burden countries such as Botswana or Eswatini. Sixteen studies assessed downward spillover effects (adults to children), and only one study explicitly assessed upward spillover effects (working-age adults to older adults). The remaining studies did not fully specify the direction. Beneficial spillover effects were documented across multiple domains: (1) Wealth and labour: reducing distance to an ART facility by 5.8 km increased household savings by 50% in Malawi; ART prevented asset loss in South Africa. (2) Health and healthcare utilisation: home-based ART in Uganda was associated with an 81% reduction in mortality among HIV-negative children; risky sexual behaviour among household members decreased from 29% to 15% at 24 months. (3) Food security and nutrition: in Kenya, ART was associated with a 0.60 SD increase in weight-for-age in children under 5 over 6 months. (4) Schooling: a Kenyan RCT found universal HIV testing and treatment increased primary school completion by 7% after 3 years; in Zambia, ART availability increased the probability of being in the appropriate grade for age by nearly 50%. (5) Caregiving: ART reduced assistance with daily living activities by up to 41% in an urban South African cohort. (6) Coresidence: a 1% increase in national ART coverage was associated with a 0.7 percentage point reduction in the probability of an older adult living without a working-age adult. Detrimental spillover effects were reported in only three studies, including a 15.2 percentage point increase in the probability of missing a meal among adults and an 8.9 percentage point increase among children in the first year after ART initiation in South Africa, attributed to regained appetite and transportation costs.
**Clinical Implications:** ART generates substantial intergenerational spillover effects across health and non-health sectors in SSA, improving economic outcomes, education, nutrition, and household stability for both children and older adults. The findings suggest that the full societal returns of ART investments are likely underestimated when only direct effects on treated individuals are considered. Negative spillover effects, though limited, highlight the need for supportive interventions such as food assistance during the first year of ART. Future research should prioritise causal study designs, upward spillover effects to older adults, and studies in high-burden countries currently lacking evidence. Policymakers should account for these broader societal benefits when evaluating the cost-effectiveness of continued HIV funding.