A significant number of individuals receiving mental health care exhibit a history of traumatic experiences. Accompanying dissociative symptoms often amplify the complexity of their required treatment. This article introduces a novel understanding and treatment approach for post-traumatic stress symptoms, inclusive of dissociation, derived from attachment and mentalization theories. Initially, we outline the different expressions of dissociation and the prevailing knowledge concerning their associations with diverse clinical manifestations and their role in trauma. We subsequently reinterpret these clinical symptoms through an attachment and mentalization lens, then proceed to elaborate on the new trauma-focused mentalization-based treatment and its therapeutic objectives. The article culminates with a case study that exemplifies the application of this approach in a clinical setting.