Individuals with autism spectrum disorders supposedly have an affinity with information and communication technology (ICT), making it an ideally suited media for this population. Virtual environments (VEs)--both two-dimensional and immersive--represent a particular kind of ICT that might be of special benefit. Specifically, this paper discusses the importance of psychological theory for VE designed for this population. I describe the contribution that different theories of autism (e.g., theory of mind, executive function, weak central coherence theory) have made and can make, as well as the potential of other non-autism-specific theories (e.g., embodied cognition). These technologies not only illuminate our understanding of autism, but they can also be used to develop new technologies for people without autism. So, as well as being an area of specialism, I argue that VE research in autism has extended--and will go onto--the boundaries of human-computer interaction more generally. This is because autism provides a unique window into human social communication and learning. Further, this field offers a chance for better inclusivity for individuals with autism within a digital society. (Contains 4 notes.)