This study examined the agreement of perceived health-related quality of life (HRQOL) between caregivers and autistic children and adolescents (n = 133, 5-12 years) using the Pediatric Quality of Life Inventory Generic Core Scales, Fourth Edition (PedsQL 4.0). Results reveal good to excellent agreement over this age range across the total, physical, and psychosocial health scales. However, the emotional, social, and school functioning scores demonstrated lower agreement in dyads with children aged 5-7 than in dyads with children aged 8-12 years. Despite these differences in agreement, overall, the PedsQL 4.0 caregiver-module is a reliable instrument for measuring HRQOL in autistic individuals aged 5-12 years.