Background: As a group, autistic children with high support needs (with adaptive functioning in the range of an intellectual disability) are at risk of significant literacy difficulties. We investigated the parent-reported home literacy environment of this group of children. Method: Sixty-two parents of autistic children (4.5 to 18.25 years) attending an autism-specific school completed a home literacy survey reporting on their child's: (1) alphabet knowledge, (2) interest in reading, (3) activities/interactions around books, (4) reading ability, and (5) writing ability. Results: We found significant positive correlations between parent-reported child interest in reading and literacy-related interactions and skills, but not with child age. Children using spoken words to communicate obtained significantly greater scores on four home-literacy subscales, but not on reading interest. Conclusions: A better understanding of the home literacy activities of autistic children with high-support needs is needed to inform educational practices aimed at promoting literacy development in this vulnerable population.