The Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders (UP; Barlow, Allen, & Choate, 2004) is a transdiagnostic cognitive behavior therapy for emotional disorders that addresses mood, anxiety, somatoform, and borderline personality disorders. Patients diagnosed with dissociative identity disorder (DID) form a nontrivial subset of patients. Extant treatment guidelines (ISSTD, 2011) emphasize the need to strive for fusion of identities (i.e., the creation of a unified sense of self). In contrast, the UP strives to inculcate an array of adaptive emotion skills, including cognitive reappraisal, emotional awareness, and affect tolerance, prior to planned exposure to traumatic memories. In this study, we provide the first assessment of the effectiveness of the UP with 5 individuals diagnosed with DID and co-occurring disorders and symptoms tracked at multiple time points. After 18–22 sessions, 4 patients exhibited significant reductions in anxiety, depression, and dissociative symptoms, and increases in emotional regulation, with significant improvements in symptomatology maintained after follow-ups of 1, 3, and 6 months. A fifth participant with prominent suicidal ideation was treated for 42 sessions and achieved comparable reductions in symptoms. None of the patients met criteria for DID or any other disorder at 6-month follow-up.