Background: Empirical studies suggest that individuals with intellectual disabilities (ID) have difficulties in conceptualising dreams as perceptually private, non-physical, individuated and potentially fictional entities. The aim of the current study was to replicate the results found by Stenfert Kroese et al. using a comparative sample size, and to examine putative cognitive correlates of accurate dream conceptualisation [receptive language and 1st order theory of mind (ToM) abilities]. Method: Conceptualisation of dreams, real objects and photographs was assessed with a structured closed-question interview schedule, together with receptive language, and ToM abilities. Results: Findings from the current study replicated those of previous research, finding that many adults with ID tend to think that dreams take place around them, can be witnessed by others, can be touched and manipulated, can be shared by others and are about real events. The ability to accurately conceptualise dreams was found to increase along with receptive language ability, and there was a non-significant association between ToM ability and the ability to understand that dreams can be about potentially fictional entities. Conclusions: Some individuals with ID have a different understanding of mental phenomena such as dreams, which has implications for several aspects of care and support, particularly relating to mental health and therapeutic work.