SUMMARY/ABSTRACT Shorter sleep duration has been consistently associated with childhood obesity, and the American Academy of Pediatrics recommends that pediatricians promote sleep as part of their obesity prevention efforts. The pediatric primary care setting has enormous potential to promote sleep, but a lack of time at the point of care is a key barrier, and insufficient sleep and childhood obesity are not equally distributed across sociodemographic groups. To overcome these barriers, mobile health platforms need to be developed to deliver behavioral sleep promotion remotely in the home setting, with tailoring to individual and contextual factors to help ensure equitable effectiveness across sociodemographic groups. Multi-component sleep promotion interventions have been developed, and initial findings suggest that behavioral sleep interventions are effective. However, these interventions have not been designed for remote delivery in the pediatric primary care context. Furthermore, the individual components have not yet been optimized, meaning some components may be ineffective or counter- effective. The study team’s objective is to engineer a mobile health platform for the pediatric care setting to promote longer sleep duration for childhood obesity prevention. Their central hypothesis is that they will identify an optimal set of intervention components to increase sleep duration and prevent excess weight gain, with equitable effectiveness across sociodemographic backgrounds. This hypothesis will be tested by pursuing three specific aims and will be guided by the Multiphase Optimization Strategy (MOST) framework. Under aim 1, an optimization trial will be conducted using an innovative experimental design to determine optimal component settings for sleep promotion. A total of four candidate components will be experimentally tested: 1) a sleep goal component, 2) a digital messaging component, 3) a parent-directed incentive component, and 4) a personalized feedback component. An advisory board (family, youth, and clinicians) will provide feedback throughout to ensure acceptability of the component content. Under aim 2, the investigative team will determine if optimal settings for sleep promotion lead to lesser gains in fat mass index. They will also measure total energy intake and the timing and composition of meals to gain mechanistic insights. Under aim 3, the investigators will determine if optimal settings for sleep promotion are comparable across individual- and neighborhood-level sociodemographic factors. This innovative research shifts attention from the problem of insufficient sleep to a solution for insufficient sleep, and represents the first application of the MOST framework to engineer a mobile health platform to promote sleep for obesity prevention that will be equitable across sociodemographic groups. The proposed research will greatly advance the field of behavioral sleep medicine and reimagine how insufficient sleep duration and o...