Stimulus overselectivity refers to maladaptive narrow attending that is a common learning problem among children with intellectual disabilities and frequently associated with autism. The present study contrasted overselectivity among groups of children with autism, Down syndrome, and typical development. The groups with autism and Down syndrome were matched for intellectual level, and all three groups were matched for developmental levels on tests of nonverbal reasoning and receptive vocabulary. Delayed matching-to-sample tests presented color/form compounds, printed words, photographs of faces, Mayer-Johnson Picture Communication Symbols, and unfamiliar black forms. No significant differences among groups emerged for test accuracy scores. Overselectivity was not statistically overrepresented among individuals with autism in contrast to those with Down syndrome or typically developing children.