This study focuses on the relationship between content elements and mental-state language in narratives from twenty-seven children with autism (ASD), twelve children with language impairment (LI), and thirty typically developing children (TD). The groups did not differ on chronological age (10;6–14;0) and non-verbal cognitive skills, and the groups with ASD and TD did not differ on language measures. The children with ASD and LI had fewer content elements of the storyline than the TD children. Compared with the TD children, the children with ASD used fewer subordinate clauses about the characters’ thoughts, and preferred talking about mental states as reported speech, especially in the form of direct speech. The children with LI did not differ from the TD children on these measures. The results are discussed in the context of difficulties with socio-cognition in children with ASD and of language difficulties in children with LI.