Objective: Individuals with autism spectrum disorder (ASD) participate in less physical activity (PA) and more sedentary behavior than their peers without ASD. Methods: The study employed Chi-square analyses of the NSCH 2016–2017 data to compare PA, TV/video watching/gaming, and usage of portable electronic devices by children with and without ASD by age and ASD severity. Results: Results suggest more than two and a half times as many children 6–11 and 12–17 years old with ASD failed to engage in 60 min of PA during the past week compared to peers without ASD. As children aged, their PA time decreased, with a larger percentage drop for children with ASD. For children ages 6–11 years, an inverse relationship was found between PA and ASD severity that was not found for older children. As the children got older, children with ASD spent more time watching TV/video watching/gaming than peers without ASD, with differing results by ASD severity. More children Birth to 5 years ASD used portable electronic devices than their peers without ASD and more young children with ASD used devices for 3 or more hours a day. Roughly the same proportions of children 12–17 years old used devices for more than 3 h a day but differential results were found between children with and without ASD for less than 1 h of device use. Conclusions for Practice: These data can be used to advocate for individualized PA interventions and services to increase PA and decrease sedentary behaviors of children with ASD.