Mental, emotional, and behavioral (MEB) disorders begin in early childhood, with one in six US preschoolers aged 3-5 years diagnosed with a MEB disorder. Children from low income and economically marginalized (LIEM) backgrounds have a higher risk of being diagnosed with MEB disorders than those from higher income families. To address the mental and physical health disparities based on socioeconomic status, ethnicity/race, and urban/rural residency, the proposed study will target Head Start racially/ethnically diverse preschoolers from LIEM backgrounds in both urban and rural areas. Guided by the Actor-Partner Interdependence Model, the Allostatic Load Model, and the Transactional Theory of Stress and Coping, the proposed 16-week Food-Body-Mind intervention includes: 1) a school-based mindfulness component delivered to equip preschoolers with knowledge and skills in mindful eating and movement (e.g., yoga, deep breathing exercises); 2) a home-based mindfulness component to increase caregivers' skills in practicing mindful eating, movement, and parenting behaviors at home to foster a more positive, mindful, and healthy home environment; and 3) a school learning and home practice connection component to improve caregiver-preschooler relationships. The purpose of this 5-year cluster randomized controlled trial is to evaluate the effects of the 16-week school- and home-based, multi-component, Food-Body-Mind intervention on improving both preschoolers' and caregivers' MEB and physical health. The long-term goal is to achieve optimal whole child health in early childhood to foster a healthier generation in the US. Fifty Head Start daycare centers will be randomized into the intervention (n=25: 8 urban and 17 rural daycare centers) or usual care control group (n=25: 8 urban and 17 rural daycare centers). Five caregiver-preschooler dyads will be recruited from each daycare classroom (total 400 dyads from 80 daycare classrooms: 200 urban dyads and 200 rural dyads). Analyses will be based on the intention-to-treat principle. The three aims are to: 1) determine effects of the intervention on improving preschoolers' mental (chronic stress by hair cortisol), emotional (sadness, fear, anger, positive affect), behavioral (problem behaviors, social skills), and physical health (BMI z-score, % body fat) from baseline (0 month) to 4 months (immediate post-intervention) and to 16 months post-baseline (12-month F/U) when compared to control group in geographically diverse urban and rural Head Start daycare sites; 2) examine intervention effects on improving caregivers' physical (BMI, % body fat, blood pressure) and mental (stress, anxiety, depression) health from 0 to 4 months and to 16 months (12-month F/U) compared to control; and 3) explore the potential mediators (caregiver mindfulness, physical activity, F/V intake, caregiver-preschooler relationship, and caregiver coping) of intervention effects on preschoolers' MEB and physical health and caregivers' physical and mental health from 0 to 4 months and to 16 months (12-month F/U). Results from this study will improve the evidence base of complementary and integrative health approaches that can be delivered in geographically diverse daycare settings.