This bulletin presents information on the youth detention population in Australia, focusing on quarterly trends from June 2013 to June 2017. Among the 964 young people in detention on an average night in the June quarter 2017, high proportions were male (91%), aged 10–17 (84%), unsentenced (64% excluding Victoria) and Aboriginal or Torres Strait Islander (53%). Over the 4-year period to the June quarter 2017, the numbers and rates of young people in detention remained stable, with minor fluctuations across quarters.