Theory of mind is the ability to attribute mental states—belief, intent, desire, pretending, knowledge, etc.—to oneself and others and to understand that others have mental states that are different from one's own and also reality. Regarding the considerable impairment of communication abilities in children with autism, the present study addresses the relationship between Theory of Mind and language, as well as those components of language that explain the abilities involved in ToM, in these children. The subjects comprised 110 children with autism, aged 4 to 16, who were evaluated using the Persian version of The Test of Language Development (Hassanzadeh & Minaei, 2002) and False Belief Tasks (Wimmer& Perner, 1983). The results of analysis of data revealed significant impact of subtests of grammatical understanding, picture vocabulary and oral vocabulary on the Theory of Mind in autistic children.