This editorial explores dual harm – the co-occurrence of self-harm and aggression – particularly among forensic populations. Historically approached as two separate and even opposing behaviours, emerging evidence shows that those who engage in self-harm and aggression experience greater adversity and poorer outcomes. This underscores the importance of enhancing our understanding of dual harm. We review key developments within the field, including how dual harm may be best conceptualised and managed, and identify critical gaps in the literature. In order to improve the care and outcomes of those who engage in self-harm and aggression, emphasis is placed on adopting more integrated approaches that consider the duality of these behaviours, as well as the complex needs of this high-risk group, within research and practice.