Negative cognitions about oneself, others, and the world are central to the development and maintenance of posttraumatic stress disorder (PTSD). We provide a comprehensive review of the literature examining the change in post-trauma negative cognitions in PTSD treatments. We explore the association between change in cognitions and change in PTSD symptoms and the mediational effect of negative cognitions on PTSD symptoms. A review of over 2000 manuscripts resulted in 65 PTSD treatment articles for review that included a measure of negative post-trauma cognitions and PTSD severity. Several studies found that PTSD treatments are associated with concurrent reductions in PTSD symptoms and negative post-trauma cognitions. Many studies suggest that the degree of reduction in negative post-trauma cognitions is both associated with the degree of reduction in PTSD symptoms and may mediate the change in PTSD symptoms in treatment. PTSD treatments are associated with significant improvements in negative post-trauma cognitions that often precede and predict reductions in PTSD symptoms.