The use of current adaptive behavior measures in practice and research is limited by their length and need for a professional interviewer. There is a need for alternative measures that more efficiently assess adaptive behavior in children and youth with autism spectrum disorders (ASDs). The Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT) is a computer-based assessment of a child's ability to perform activities required for personal self-sufficiency and engagement in the community. This study evaluated the applicability, representativeness, and comprehensiveness of the Daily Activity, Social/Cognitive, and Responsibility domains for children and youth with an ASD. Twenty professionals and 18 parents provided feedback via in-person or virtual focus groups and cognitive interviews. Items were perceived to represent relevant functional activities within each domain. Child factors and assessment characteristics influenced parents' ratings. In response to feedback, 15 items and additional directions were added to ensure the PEDI-CAT is a meaningful measure when used with this population. (Contains 3 tables.)