This study employed the self-understanding interview of Damon and Hart (1988) to assess the self-concepts of two groups of children and adolescents: a group of individuals with autism and a group of nonautistic mentally retarded individuals who were matched for age and for verbal ability. On the basis of an hypothesis concerning the interpersonal origins of social and psychological self-concepts (Hobson, 1990; Neisser, 1988), it was predicted that the participants with autism would show a relative dearth of such concepts in their talk about themselves. In accordance with our predictions, there was a significant group difference in the number and quality of statements that fell into the social category of self-concept; contrary to our predictions, however, there was no group difference in the number of statements that fell into the psychological category. In addition, although there were not significant group differences in the overall production of verbally expressed concepts concerning self-attributes of a physical, active, or psychological kind, even within these categories individuals with autism made fewer references to social interactions or qualities. These results are discussed with regard to theories of self-concept development in typically developing as well as autistic and mentally retarded individuals, and with reference to the limitations of interpersonal understanding (“theory of mind”) in people with autism.