Decreased engagement in beneficial physical activity and increased levels of sedentary behavior and unhealthy weight are a continued public health concern in adolescents. Adolescents with autism spectrum disorder may be at an increased risk compared with their typically developing peers. Weekly physical activity, sedentary behavior, and body mass index classification were compared among adolescents with and without autism spectrum disorder. Analyses included 33,865 adolescents (autism spectrum disorder, n = 1036) from the 2016-2017 National Survey of Children's Health (United States). After adjustment for covariates, adolescents with autism spectrum disorder were found to engage in less physical activity and were more likely to be overweight and obese compared with their typically developing peers (p's < 0.05). As parent-reported autism spectrum disorder severity increased, the adjusted odds of being overweight and obese significantly increased and physical activity participation decreased (p-for-trends < 0.001). The findings suggest there is a need for targeted programs to decrease unhealthy weight status and support physical activity opportunities for adolescents with autism spectrum disorder across the severity spectrum.