With the publication of DSM-5, posttraumatic stress disorder (PTSD) is no longer considered an anxiety disorder, but there is extensive evidence that PTSD is associated with high levels of comorbid mood and anxiety disorders. Although effective treatments exist for PTSD (e.g., Cognitive Processing Therapy), current treatments were not designed to target the full range of comorbid conditions associated with this disorder, and it is unclear whether these treatments are effective for comorbid conditions for individuals with PTSD. The Unified Protocol for Transdiagnostic Treatment of Emotional Disorders (UP), therefore, has great promise as a potential treatment for PTSD. This chapter reports the results of a case series of the UP for three individuals with a primary diagnosis of PTSD. Results of the UP were promising, with all three reporting a significant drop in symptoms of PTSD, anxiety, and depression. Implications for evaluating the UP as an alternative treatment for PTSD are also discussed.