There is evidence to suggest that social support may be an important resource for the mental and physical health of caregivers and children affected by HIV/AIDS, especially in HIV-endemic areas of the developing world. Drawing from theory on social relations and health, in this paper we argue that it is important to assess not only the existence and direction of associations, but also the effects and processes explaining these. We refer to House et al’s (in Annu Rev Sociol 14;293–318, 1988) theoretical framework on social support structures and processes as a guide to present and discuss findings of a systematic review of literature assessing the relationship between social support and health among caregivers living with HIV or caring for HIV/AIDS-affected children. Findings confirm the importance of social support for health among this population, but also expose the absence of empirical work deriving from the developing world, as well as the need for further investigation on the biopsychosocial processes explaining observed effects.