Abstract: Objective: Prior studies have demonstrated a robust link between posttraumatic stress disorder (PTSD) symptoms and suicide attempts among military personnel; however, to our knowledge, no study has examined PTSD in relation to indices of suicide attempt seriousness. Accounting for the multifaceted nature of suicide attempts is especially important for service members who often face unique stressors and are at increased risk for severe outcomes, including death. Method: Using secondary analyses of data collected for a large assessment study, we examined the connection between PTSD symptoms and seriousness of suicide attempts in psychiatrically hospitalized service members referred to inpatient care following a suicide attempt (N = 121). We used a modified version of the PTSD Checklist-Military Version and the Suicide Intent Scale to assess PTSD symptoms and suicide attempt seriousness, respectively. Results: Our findings demonstrated that higher PTSD symptom total and cluster scores were associated with an increased seriousness of suicide attempts. Conclusions: Our Results: indicate the need for intervention programs targeting PTSD symptoms among service members, including interventions delivered in inpatient psychiatric settings, to reduce the risk of fatal self-harm. Implications for mental health professionals and military support systems to mitigate suicide risk through targeted interventions focused on PTSD symptoms are discussed.