Children with autism may have difficulties in audiovisual speech perception, which has been linked to speech perception and language development. However, little has been done to examine children with Asperger syndrome as a group on tasks assessing audiovisual speech perception, despite this group's often greater language skills. Samples of children with autism, Asperger syndrome, and Down syndrome, as well as a typically developing sample, were presented with an auditory-only condition, a speech-reading condition, and an audiovisual condition designed to elicit the McGurk effect. Children with autism demonstrated unimodal performance at the same level as the other groups, yet showed a lower rate of the McGurk effect compared with the Asperger, Down and typical samples. These results suggest that children with autism may have unique intermodal speech perception difficulties linked to their representations of speech sounds. Autism Res 2014, 7: 50–59. © 2013 International Society for Autism Research, Wiley Periodicals, Inc.