The theory of mind account of autism suggests that the key social, communicative and imaginative impairments which characterise this disorder result from an inability to represent mental states. While this account has been largely confirmed by experimental work, there has, as yet, been little examination of autistic children's theory of mind outside the laboratory. The present study used the Vineland Adaptive Behavior Scales to measure real life social adaptation, through the report of care-givers. In particular, we were interested to find out more about the real life competence of those few autistic subjects who do pass tests of theory of mind. Autistic, mentally handicapped and normally developing children were tested with two standard theory of mind tasks. Groups of subjects who passed or failed these tasks were contrasted. We supplemented the Vineland Scales with items designed to distinguish social behaviour which necessitates theory of mind (termed Interactive) and social behaviour which could be learned (Active). We also asked about maladaptive behaviour of two sorts: Bizarre behaviour typical of autism, and Antisocial behaviour at least some of which would appear to require consideration of beliefs (e.g. deception). We found that the normally developing and mentally handicapped children showed a great deal of evidence of “mind-reading” in their everyday lives, regardless of theory of mind task performance. By contrast, in the autistic group, only those individuals who passed the false belief tasks showed insightful Interactive and Antisocial behaviour. These passers also had better verbal and communication abilities. The autistic subjects who failed the laboratory tasks showed little or no evidence of understanding mental states in their everyday lives, but many did show a high degree of simple Active sociability. Closer analysis showed that only some of the passers showed good evidence of theory of mind in their real life behaviour, and that even these were somewhat impaired relative to their age and developmental level. Implications for the theory of mind account of autism are discussed.