Samples in prior studies examining attachment theory in the military have been predominantly composed of male combat veterans. Given the rates of sexual trauma among female veterans and differences in the association between attachment and posttraumatic stress disorder (PTSD) severity for sexual trauma survivors, it was necessary to consider the attachment characteristics of veterans within a mixed-sex sample. Participants were a mixed-sex veteran sample seeking inpatient trauma-related treatment (N = 469). Using independent samples t tests, we examined sex differences in attachment. Consistent with our hypothesis, women reported a higher level of attachment anxiety than did men, t(351) = −2.12, p =.034. Women also reported a higher level of attachment avoidance, t(351) = −2.44, p =.015. Using hierarchical regression, we examined the contribution of attachment anxiety and avoidance to PTSD severity, partialing out variance accounted for by demographic variables and traumatic experiences. Consistent with our hypotheses, attachment avoidance predicted PTSD severity on the Clinician-Administered PTSD Scale for DSM-IV (CAPS), β =.20, p <.001, and the PTSD Checklist–Civilian Version (PCL-C), β =.18, p <.001. Attachment anxiety did not predict CAPS severity but did predict PCL-C severity, β =.11, p =.020. These results suggest the association between attachment avoidance and PTSD is not exclusive to combat trauma and may apply more generally to the larger veteran population. Higher levels of attachment anxiety and avoidance among female veterans potentially implicate the presence of greater attachment fearfulness among this particular subpopulation of veterans.