Objective: This study evaluated the relations between posttraumatic stress disorder (PTSD) symptoms and poor family functioning in veterans and their partners. Method: Data were collected from Caucasian veterans with PTSD (N = 1,822) and their partners (N = 702); mean age = 53.9 years, SD = 7.36. Veterans completed the Posttraumatic Checklist Military Version (PCL-M) and, along with their partners, completed the McMaster Family Assessment Device (FAD-12). Assessments were conducted at intake into a treatment program at 3 months and 9 months posttreatment. Results: Structural equation models (SEMs) were developed for veterans as well as for veterans and their partners. Poor family functioning for veterans at intake predicted intrusion ([beta] = 0.08), hyperarousal ([beta] = 0.07), and avoidance ([beta] = 0.09) at 3 months posttreatment. At 3 months posttreatment, family functioning predicted hyperarousal ([beta] = 0.09) and avoidance ([beta] = 0.10) at 9 months. For veterans and their partners, family functioning at intake predicted avoidance ([beta] = 0.07) at 3 months, and poor family functioning at 3 months predicted intrusion ([beta] = 0.09) and hyperarousal ([beta] = 0.14) at 9 months. The reverse pathways, with PTSD symptoms predicting poor family functioning, were only evident with avoidance ([beta] = 0.06). Conclusion: Family functioning may play a role in treatment for veterans. (Contains 3 tables, 2 figures and 1 footnote.)