PurposeThis work aims to assess the association of sleep duration with cardiometabolic risk (adiposity, blood pressure, lipids, albuminuria and A1C) and to investigate lifestyle factors (physical activity, light exposure, caffeine consumption and sugar consumption) associated with sleep duration in children.MethodsA nationally representative sample of 3907 children ages 6–17 years enrolled in NHANES from 2011 to 2014 was included in this cross‐sectional study. Sleep duration was defined as the daily average time spent sleeping over 7 days as measured by a physical activity monitor (PAM). Participants without valid sleep data for ≥95% of the study were excluded. Regression models were adjusted for age, sex, race, body mass index (BMI) Z score, physical activity and light exposure.ResultsIn adjusted regression models, longer sleep duration was associated with lower systolic blood pressure index (β = −3.63 * 10−5, 95% CI −6.99 * 10−5, −2.78 * 10−6, p = 0.035) and BMI Z score (β = −0.001, 95% CI −0.001, 0.000, p = 0.002). In logistic regression models, longer sleep duration was associated with lower odds of obesity (OR = 0.998, 95% CI 0.997, 0.999, p < 0.001) and overweight status (OR = 0.998, 95% CI 0.997, 0.999, p = 0.004). Greater light exposure (β = 6.64 * 10−5, 95% CI 3.50 * 10−5, 9.69 * 10−5, p < 0.001) and physical activity (β = 0.005, 95% CI 0.004, 0.006, p < 0.001) were associated with longer sleep.ConclusionLonger sleep duration was associated with lower blood pressure and adiposity measures in children. Improving sleep quality by increasing physical activity and light exposure in childhood may decrease the lifetime risk of cardiometabolic disease.