The ageing of the population will increasingly result in reliance on the family for care in the community. Existing reviews have provided insights into the needs and health outcomes of family caregivers, but are disproportionately skewed towards spousal caregivers. Presently, a large majority of family caregivers are adult children. Adult children are distinct from spousal caregivers in terms of the combination of roles they occupy and the relationship they have with the care recipient. These unique considerations can have important implications for their well-being. A growing body of literature has investigated the factors that contribute to adult children caregivers' (ACCs) well-being; however, no reviews to date have synthesised this body of literature or appraised its methodological quality. Our objective was to identify the range and types of factors that contribute to ACC well-being across studies. A scoping review was conducted. Medline, Psycinfo, EMBASE and CINAHL databases (January 1996–August, 2012) were systematically searched for studies investigating ACC well-being. Inclusion/exclusion criteria were applied, methodological quality was appraised, the data were charted and a narrative synthesis was conducted. Fifty-five studies met our inclusion criteria. Factors that contribute to ACC well-being were found to be either: (i) care recipient-related (e.g. nature of limitations, amount of care required); (ii) caregiver-related (e.g. psychological dispositions of the ACC); or (iii) socially embedded (e.g. parent–child relationship, multiple role involvement, social support available to the ACC). Socially embedded factors that contribute to ACC well-being have received the most attention in the literature. Among these factors, ACC well-being is uniquely impacted by the quality of the parent–child relationship and combination of roles occupied. The majority of studies were cross-sectional. Future studies should therefore employ a longitudinal design to inform our understanding of the changes that take place in the parent–child relationship and multiple role involvement across the care-giving trajectory.