Sperber and Wilson's (1986) relevance theory makes explicit the role of the comprehension of intentions in human communication. Autistic people have been hypothesized to suffer from a specific and characteristic impairment in the ability to attribute such mental states (e.g., beliefs, intentions); a lack of "theory of mind". According to relevance theory, then, autistic people should have specific difficulties with the use of language for communication. Relevance theory allows precise predictions about the levels of communicative competence that should be possible with either no, first-order only, or second-order theory of mind ability. Three experiments are reported which tested predictions following from the analysis of figurative language in terms of relevance and theory of mind, in able autistic and normal young subjects. The results lend support to relevance theory. In addition, the findings suggest that some autistic subjects are eventually able to attribute mental states. Lastly, the results demonstrate close links between social and communicative understanding in autism and normal development.