Background: Research has established beneficial associations between 24-hour movement guideline adherence and several health outcomes in typically developing (TD) children, but these relationships are poorly understood in children with neurodevelopmental disorders (NDD). This study examined (1) 24-hour movement guideline adherence, (2) the influence of disability severity, and (3) associations between guideline adherence and health outcomes of TD children and children with NDD. Methods: This cross-sectional study used data from the 2018 and 2019 cycles of the US National Survey of Children’s Health. Parental/caregiver reports of movement behaviors (physical activity, screen time, and sleep), disability severity (limitations to daily activities), and health outcomes (general health status, anxiety, and depression) were provided for 8554 children with NDD and 19,669 TD children aged 6–17 years. Results: Children with NDD had significantly lower odds of meeting each movement behavior guideline compared to TD children; these effects were most pronounced for those who experienced consistent limitations to daily activities. Meeting at least 2 guidelines significantly lowered the odds for anxiety and depression, and increased the odds for better general health for children with NDD. Discussion: These findings suggest that degree of disability severity has a strong influence on adherence to 24-hour movement guidelines among children with NDD.