Abstract: Posttraumatic stress disorder (PTSD) is a debilitating condition affecting military populations, with a higher prevalence compared to the general population. Despite the development of first-line trauma-focused treatments such as Cognitive Processing Therapy (CPT) and Prolonged Exposure Therapy (PE), a significant proportion of patients continue to experience persistent PTSD symptoms following treatment. This study utilized network analysis to explore the PTSD symptom network's dynamics pre- and post- trauma-focused treatment and investigated the role of military sexual trauma (MST) history in shaping the network. Network analysis is a novel approach that can guide treatment target areas. The sample was comprised of 1648 service members and veterans who participated in a two-week intensive PTSD treatment program, which included completion of evidenced-based individual therapy as well as skill-building focused group therapy. PTSD severity was assessed using the PTSD Checklist for DSM-5 at baseline and post-treatment. Network analyses revealed strong connections within symptom clusters, with negative emotions emerging as one of the most central symptoms. Interestingly, the symptom network's overall structure remained stable following treatment, whereas global strength significantly increased. MST history did not significantly impact the network's structure or its change relative to treatment. Future research should further examine whether targeting negative emotions optimizes PTSD treatment outcomes for military populations.