Background:Children with Autism Spectrum Disorders (ASD) may be at greater risk for not meeting physical activity (PA) guidelines than neurotypical children (NT). The purpose of this study was to explore setting (free play versus organized) and social group composition influences on PA of children with ASD during summer camp.Methods:Data were collected on 6 ASD and 6 NT boys (aged 5 to 6 years) attending an inclusive summer camp. During free play and organized activity, research assistants observed the camp’s social environment and children’s PA using a modified version of the Observational System for Recording Physical Activity of Children—Preschool version.Results:In free play, children with ASD spent significantly less time in Moderate-Vigorous PA (MVPA) while with a peer (1.2%), compared with a peer group (11.5%) or alone (13.2%). They demonstrated significantly more Light-Moderate-Vigorous PA (LMVPA) while in a solitary social context (68.2%) compared with alone with an adult (25.8%), alone with a peer (34.8%), or with a peer group (28.2%). No significant differences were noted during organized activity.Conclusion:Features of the social environment may influence PA levels of children with ASD. Specifically, certain social group contexts may be more PA-promoting than others depending on the setting.