This chapter describes the underlying principles for Schema Therapy (ST) and its forensic adaptation, and illustrates the forensic model with a case example. It presents the current status of the evidence of ST in forensic settings and make suggestions for future research on ST. ST combines different elements from various therapeutic approaches. ST distinguishes five universal emotional needs: the need for secure attachment; autonomy and independence; limits and boundaries; validation of needs and feelings; and spontaneity and play. The main concepts of the ST approach are early maladaptive schemas, dysfunctional coping styles and schema modes. In the initial assessment phase, the therapist works together with the patient to assess the patient's early maladaptive schemas and dysfunctional coping responses, exploring the origins and links to the patient's presenting problems, such as addiction and criminal/aggressive behaviour. Behavioural interventions are targeted at dysfunctional behavioural patterns and practice of new, more adaptive coping.