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 (β = .08), hyperarousal (β = .07), and avoidance (β = .09) at 3 months posttreatment. At 3 months posttreatment, family functioning predicted hyperarousal (β = .09) and avoidance (β = .10) at 9 months. For veterans and their partners, family functioning at intake predicted avoidance (β = .07) at 3 months, and poor family functioning at 3 months predicted intrusion (β = .09) and hyperarousal (β = .14) at 9 months. The reverse pathways, with PTSD symptoms predicting poor family functioning, were only evident with avoidance (β = .06). CONCLUSION: Family functioning may play a role in treatment for veterans.