Objective: This study examined the relationship among childhood trauma, posttraumatic stress disorder (PTSD) symptoms, and adult social support in a large sample of veterans who served in the military after 09/11/2001, with a specific focus on the potential role of the PTSD avoidance and numbing cluster as intervening in the association between childhood abuse and adult functional social support. Method: Participants were 1,301 veterans and active duty soldiers who have served in the military since 09/11/2001; a subsample of these participants (n = 482) completed an inventory of current functional social support. Analyses included linear regression and nonparametric bootstrapping procedures. Results: After controlling for combat exposure, exposure to childhood trauma was associated with PTSD symptoms in adulthood. Further, PTSD symptoms, and particularly PTSD avoidance/numbing cluster symptoms, intervened in the relationship between childhood trauma and adult functional social support. Conclusions: Findings support the association of childhood trauma (both abuse related and other, non-abuse related trauma) with PTSD symptoms in military personnel and veterans, even after accounting for combat exposure. Additionally, the avoidance and numbing symptom cluster of childhood trauma-based PTSD may be particularly salient in compromising one's subsequent ability to garner functional social support in adulthood. (Contains 3 tables.)