Enhancing children's sleep may be a novel approach for prevention of obesity and cardiovascular (CV) disturbance. Observational studies with children demonstrate that short sleep increases risk of obesity and other CV risk factors. Randomized controlled trials with children 8-11 years old demonstrate that enhancing sleep duration leads to positive changes in eating and activity behaviors and weight status, particularly for children who enhance their sleep the most. Enhancing sleep may be particularly important for racial minority children and those from lower socioeconomic backgrounds given their increased risk for short sleep, obesity and CV risk factors. In this study two active obesity preventive interventions will be evaluated: a) enhancing sleep alone (Optimize Sleep [OS]), and b) enhancing sleep along with eating and activity behaviors that have demonstrated efficacy for obesity prevention and are implicated in self-regulatory pathways related to sleep (i.e., energy dense snack foods and beverages, TV viewing, and physical activity) (OS-Plus). Two hundred four children 8-11 years old who are African American/black, primarily from low socioeconomic backgrounds, and who sleep < 9.5 hours/night into a 12-month study will be enrolled. Children will be randomly assigned to either OS or OS-Plus. Over the 6-month treatment phase, all children will attend an 8-session treatment; monthly phone contacts will occur during maintenance (6-12 months). Primary aim is to determine the efficacy of OS-Plus relative to OS on change in body mass index z-score (BMIz) at end of treatment. Secondary aims will assess efficacy of OS-Plus relative to OS on additional cardiometabolic risk factors, eating and activity behaviors. Exploratory aims will assess maintenance of effects at 12 months.