A secondary study was conducted within a broader National Institutes of Health (NIH)-funded longitudinal study on resilience in South African mothers and children affected by HIV/AIDS (Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome). The aim of this study was to evaluate the effect of a 24-week support group intervention programme, which was designed to enhance adaptive behaviour of latent-phase children affected by maternal HIV/AIDS as reported by the mother participants. The study was embedded in a concurrent nested mixed-method design, with a quasi-experimental and a nested multiple case study approach. The mother and child dyads (n = 139) were purposefully selected from amongst previously identified HIV-positive women (n = 220), with children between the ages of 6 and 10 years at clinics in the Tshwane region, South Africa. Data were collected over a period of five years in multiple waves of intervention implementation. The data collection strategies comprised of mother psychological questionnaires and quality assurance questionnaires. The quantitative data were analysed by means of a paired-sample t-test for within-group comparisons. The qualitative text was analysed for themes to establish defined categories. The findings of the study showed that the mothers reported that the child support group intervention sessions decreased the children’s withdrawal-, social-, attention-, rule-breaking- and aggressive behavioural problems. The findings suggest that the use of support groups should be incorporated into intervention programmes dealing with latent-phase children affected by HIV/AIDS to enhance adaptive behaviour.