Abstract Children with neurodevelopmental disabilities (NDD) face many individual (diagnosis-specific, demographic), parent/family-related, and community-level barriers that affect their ability to optimize their health behaviors (being physically active, eating healthy, sleeping appropriately) and developmental outcomes (motor/participation, social, behavioral, cognitive/academic performance). Children with NDD are at a greater risk for poor developmental outcomes, physical inactivity, and reduced school and community-based recreational participation compared to their neurotypical (NT) peers. These challenges faced by children with NDD lead to higher rates of overweight/obesity and social isolation and in turn affect their long-term physical health (cardiovascular disease, diabetes, shorter life expectancy), psychological health (i.e., anxiety, depression, behavioral problems), and future development. Identifying and addressing the various complex, multi-level factors affecting health behaviors and developmental outcomes of children with NDD will eventually improve their overall physical/mental well-being, quality of life, as well as life expectancy. To ask these complex questions, we propose a multi/inter-disciplinary team including a physical therapist (Bhat, PL), dietitian (Robson, Co-PL), epidemiologist (Patterson, Co-PL), cardiologist (Baker-Smith, Co-PL), and data scientists (Zhang, Brewer, Co- Is) who will work together to examine the National Survey of Children’s Health (NSCH), a large national, open- source database. We will compare cross-sectional data collected across 6 timepoints from years 2016-2021 to understand differences in children’s health and development before versus during the pandemic. We will also pool data across all timepoints (N=50K-90K per year, ~94K total sample in 2021) to report patterns of children’s health behaviors, development, and factors influencing them. NSCH tracks parent-reported behaviors of neurotypical children (~70% sample, N~67,000 in 2021) along with children with various neurodevelopmental disabilities (NDD, ~30% sample, N~27,000 in 2021) such as Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorders (ADHD), Anxiety, Learning Disability (LD), Speech Delay (SD), Intellectual Disability (ID), Down Syndrome (DS), Developmental Delay (DD), Seizures, and Behavioral/Mood Problems (BP). The majority of the current literature is focused on the 2016-2017 NSCH sample. So far, no one has compared the changing trends in health and development in children with NDD using the NSCH dataset. Few studies have used a holistic perspective including complex, multi-level factors to evaluate health and developmental outcomes. We will use statistical / data science approaches (e.g., machine learning) to characterize subgroups based on various factors and identify the key and proximal factors to make recommendations for generalized and tailored interventions targeting the needs of children with NDD. In th...