To compare the national prevalence of meeting physical activity, screen time, and sleep guidelines between autistic and nonautistic children and identify factors associated with meeting these guidelines. Prevalences for each health-determining behavior were estimated using the 2022 National Survey of Children's Health, using national guidelines. Complex survey-weighted logistic regression, adjusted for demographic covariates, was used to measure associations between autism and meeting each guideline, and to identify potential child, family, community, and policy-level determinants of each behavior among autistic children. The prevalence of meeting all three guidelines was low among autistic and nonautistic children across age groups. Physical activity guidelines were met at similarly low rates among autistic and nonautistic children; however, autistic children of all age groups were less likely to meet screen time guidelines, and those in the 3-5 and 6-11 years age groups were less likely to meet sleep guidelines. Moderate/severe autism, irregular bedtime, low parental education, and lacking a medical home were associated with lower likelihood of meeting sleep guidelines. Irregular bedtime and high income were associated with lower likelihood of meeting physical activity guidelines. Autistic children meet guidelines for physical activity, screen time, and sleep at a low prevalence and less than their nonautistic peers. Clinicians should develop individualized plans to facilitate adherence to guidelines among autistic children. Interventions should address modifiable factors, including bedtime regularity and access to medical homes. Further research and policy efforts should be made to improve adherence to guidelines among autistic children and subsequently reduce health disparities.