This study provided a description of types and dimensions of informal and formal social support among aging parental caregivers of adult children diagnosed with autism spectrum disorder (ASD). Parents participated in a web-based survey regarding use of and satisfaction with social support services for parents or their adult children. Results indicated that many parents participated in autism support groups (27.5%), with psychiatric services (48.8%), counseling (40.6%), and financial assistance (39.7%) the most commonly used formal social supports. Emotional support (88.8%) and informational support (67.5%) were the most common informal social supports used. Professionals who are working with parental caregivers and their adult children diagnosed with ASD should be aware of available social support services to help them find needed services.