This chapter explores the relationship between trauma and non-suicidal self-injury (NSSI) within forensic settings. In particular, it considers prevalence rates, pathways to NSSI, and the dual risk presented by those who engage in both NSSI and violence. The primary reference group for this chapter is those in the National High Secure Healthcare Service for Women (NHSHSW) and it considers responses within this setting to understand, manage, and reduce the occurrence of NSSI, considering the impact of these on both staff and patients. The chapter advocates Trauma-Informed treatment responses for this population, drawing on the Trauma and Self-Injury (TASI) service. Interwoven throughout the chapter are the lived experiences of patients, using the patients voice as part of the narrative.