The purpose of this scoping review was to systematically synthesize barriers and facilitators for physical activity (PA) among children and youth with autism spectrum disorders (ASD) across the socioecological model. Five electronic databases were searched in March 2022 for studies examining barriers and facilitators for PA among children and youth with ASD. An updated search was performed in April 2024. The framework synthesis method was utilized, and the socioecological model was the chosen framework. Fifty-four studies published from 2008 to 2024 were included. Among the included studies, 57% included the perspectives of children and youth with ASD alone or together with proxies (eg,parents, teachers, and coaches), while 43% included only the perspectives of proxies. Barriers and facilitators on the intrapersonal and interpersonal levels were most substantial. The analysis led to 2 main categories of barriers and facilitators, those unique to children and youth with ASD, and those similar to what had been identified through research on children and youth, both typically developing and with other disabilities. This comprehensive scoping review shows the complexity of factors contributing to barriers and facilitators for PA among children and youth with ASD, and highlights both the factors unique to this population and more general factors affecting PA participation. The findings from this synthesis might be used to guide the development of inclusive PA in physical education, organized sports, and other community PA arenas.