The administration of youth justice systems in Australia is a state and territory responsibility. Almost all states and territories have in recent years undertaken extensive reviews of their youth justice systems. In addition, various oversight bodies (such as ombudsmen, inspectors of custodial services, children’s guardians and advocates), Commonwealth agencies (such as the Australian Law Reform Commission), and non-government organisations (such as Amnesty International) have also completed reviews and published reports in this area. The catalysts for some of these reviews were incidents in youth justice detention centres which captured national (and international) attention. A key theme arising from many of these reviews is the need for youth justice detention to be a measure of last resort. Detention, especially for young people who have been victims of abuse and neglect or who have mental illness and intellectual disabilities, is often detrimental and has little benefit in reducing recidivism. This paper explores this and other key themes arising from the recent reviews into Australian youth justice systems.