The current study examined delays in syntax and morphology, and vocabulary, in autism spectrum disorder (ASD). Children ages 4–6 years with ASD (n = 21) and typical development (n = 21), matched on nonverbal mental age, completed five language tasks. The ASD group had significant delays in both syntax and morphology, and vocabulary measures, with significant within-group heterogeneity; furthermore, syntactic and morphological measures were impaired even for subgroups matched on vocabulary. Children in the ASD group without early language delay showed syntactic and morphological impairment, with intact performance on vocabulary and sentence repetition. Findings indicate that syntactic and morphological impairments are a significant concern for high-functioning children with ASD, and may be overlooked if language evaluation focuses exclusively on vocabulary.