Carers of autistic adults may experience increased day-to-day stress relating to their caring role. This review aims to (1) summarise the current literature on factors that affect mental well-being in carers of autistic adults and (2) map these results to an existing conceptual model of carer psychological well-being for individuals with developmental disabilities. Twenty-three studies met inclusion criteria. Some factors, such as adaptive skills and the quality of the caring relationship, were consistently associated with carer mental well-being. Conflicting or weak associations were found with several factors, including carer age and formal services received. These findings may be mapped to the King et al. (Journal of Pediatric Psychology, 24(1), 41–53, 1999) model, and adaptations to this model are discussed.