Objective: Informal care, the provision of unpaid care to dependent friends or family members, is often associated with physical and mental health effects. As some individuals are more likely to provide caregiving tasks than others, estimating the causal impact of caregiving is difficult. This systematic literature review provides an overview of all studies aimed at estimating the causal effect of informal caregiving on the health of various subgroups of caregivers.; Methodology: A structured literature search, following PRISMA guidelines, was conducted in 4 databases. Three independent researchers assessed studies for eligibility based on predefined criteria. Results from the studies included in the review were summarized in a predefined extraction form and synthesized narratively.; Results: The systematic search yielded a total of 1,331 articles of which 15 are included for synthesis. The studies under review show that there is evidence of a negative impact of caregiving on the mental and physical health of the informal caregiver. The presence and intensity of these health effects strongly differ per subgroup of caregivers. Especially female, and married caregivers, and those providing intensive care appear to incur negative health effects from caregiving.; Conclusion: The findings emphasize the need for targeted interventions aimed at reducing the negative impact of caregiving among different subgroups. As the strength and presence of the caregiving effect differ between subgroups of caregivers, policymakers should specifically target those caregivers that experience the largest health effect of informal caregiving.;