Children with autism have delays in the development of theory of mind. However, the sub-group of children with autism who have little or no language have gone untested since false belief tests (FB) typically involve language. FB understanding has been reported to be intact in children with specific language impairment (SLI). This raises the possibility that a non-verbal FB test would distinguish children with autism vs. children with SLI. The present study tested two predictions: (1) FB understanding is to some extent independent of language ability; and (2) Children with autism with low language levels show specific impairment in theory of mind. Results confirmed both predictions. Results are discussed in terms of the role of language in the development of mindreading.