Study objective: To provide normative sleep data on 9-18 year old Australians. Design: Cohort study. Setting: Participants' homes. Participants: 4032 Australians aged 9-18 years. Interventions: N/A. Measurements and results: Participants completed a 48h use of time recall, comprising sleep data for one complete night. Sleep duration, bedtime and wake time were compared across age groups, between genders, and between school and non-school days using ANOVA. Sleep duration declined with age (P<0.0001) at the rate of 12 min/ night per year of age on school days, and 4 min on non-school days. Girls slept slightly longer than boys (5 min/ night, P=0.03). Non-school day sleep was 16 min longer than school day sleep (P<0.0001), with the difference increasing with age. Betimes got later with age (P<0.0001), however there were no differences in bedtimes between boys and girls. Bedtimes occurred 34 min later on non-school days (P<0.0001). Wake times were very similar across age groups on school days, but increased at the rate of 10 min/ year of age on non-school days. Wake times were similar for boys and girls, and occurred on average 82 min later on non-school days (P<0.0001). Overall, 17% of school days and 20% of non-school days failed to meet the American Centers for Disease Control and Prevention sleep duration guidelines. Conclusions: Normative sleep data will provide a valuable yardstick for health and education professionals when dealing with sleep-related issues.