Objective: 'Theory of mind' (ToM) arose from the study of primates and their social organization, and scholars in many fields - philosophy, anthropology, psychology, psychiatry and neuroscience - have contributed to this expanding topic. In this paper, we provide an overview of aspects of ToM of relevance to psychiatry. We briefly describe the origins of ToM in primates and humans and some relevant neurobiology, and then touch on possible contributions to psychopathology. Method: Wesearched for articles on PubMed and Medline, using the terms 'theory of mind', 'mirror neuron system' and 'psychiatry'. Conclusion: There is evidence that ToM deficits are important in certain psychiatric disorders. While more research is required, an appreciation of ToM will have an impact on our further understanding and management of at least some mental disorders, including autism and schizophrenia.