Autism spectrum disorder (ASD) is associated with deficient comprehension of figurative language and, specifically, idioms. Theories ascribe this to deficits in specific abilities (e.g., Theory of Mind [ToM]; executive functions [EF]; general language skills), but no comprehensive theory has resulted. This study investigated the differential contribution of various abilities to idiom comprehension among children and adolescents with ASD compared to matched controls with typical development (TD). The TD group outperformed the ASD group in idiom comprehension. However, whereas EF predicted idiom comprehension in the TD group, vocabulary predicted idiom comprehension in the ASD group. Our findings emphasize the link between general language competence and figurative language comprehension in ASD and point to different processing mechanisms in each group.