BackgroundThe care leaver population has been noted to have worse health outcomes than those who have not experienced state care. In order to address these differential health outcomes, it is essential that the causal factors underlying this inequality are understood. AimThis systematic review has three primary research aims: (1) to identify the key predictors of care leavers’ health; (2) to understand how determinants of health are conceptualised within the literature; and (3) to understand what methods and data sources are used to understand the health outcomes of care leavers. MethodsThrough systematic searches of academic databases (APA PsycInfo-OVID, Applied Social Science Index and Abstracts (ASSIA), Social Services Abstracts, and ProQuest Social Science Journals- Social Science Database) for peer reviewed articles, we screened 21,545 (final n = 107) studies through three levels of review. We conducted the review following the PRISMA-ScR checklist and guidelines. Eligibility criteria were: written in English; an empirical study; published in a peer-reviewed journal; included health as an independent or dependent variable; and focused upon health outcomes for care leavers, including those who had aged out and those who had experienced care during their childhood but had reached the age of majority. FindingsThe included studies suggest a range of key predictors of care leavers' health across micro, meso and macro levels, although there is a lack of consensus for some factors. Health is most commonly framed as an outcome, with care status being the primary predictor of care leavers' health. The predominant focus of studies is on the micro-level, with macro predictors of health relatively neglected and a lack of comparative studies. Almost half of the studies used secondary data, with the majority being from the USA and relying on a limited number of datasets. ConclusionGiven these findings, this review outlines a number of implications for policy and practice as well as recommendations for future research into predictors of care leavers’ health, as well as the development of robust datasets that would help facilitate this.