Enthusiasm for trauma-informed practice has grown exponentially in the last two decades. The concept was coined by Harris and Fallot (2001), and rather than provide treatment, this approach aims to ensure that all services are traumaaware, safe, compassionate and respectful (Levenson and Willis, 2019). Given the prevalence of trauma experiences among the justice-involved population (Bellis et al., 2014; Olafson et al., 2018; Levenson and Willis, 2019; Ford et al., 2019), local and international criminal justice agencies have sought to integrate traumainformed practice into service provision. This paper highlights key themes from a systematic narrative review of the international criminal justice research on traumainformed practice in the criminal justice system. All included studies focused on justice-involved women and young people, both girls and boys, but none of the studies involved justice-involved men. Five key themes were identified. Firstly, recognising trauma was important to support recovery and avoid re-traumatisation. Secondly, safety was a central consideration for justice-involved women, young people and for staff. Thirdly, trauma was experienced in abusive relationships, but healthy relationships supported recovery. Fourthly, gender-responsive, traumainformed and flexible services, including programmes, had positive benefits for women. Finally, where practitioners were committed to trauma-informed practice, they were important mediators for its integration into organisational practices.