Research suggests that subthreshold posttraumatic stress disorder (PTSD) symptomatology is associated with increased risk for psychological and functional impairment, including increased risk for suicidal ideation. However, it does not appear that any studies to date have investigated whether subthreshold PTSD can effectively be treated with evidence‐based, trauma‐focused treatment. Accordingly, we tested response to cognitive processing therapy (CPT) in 2 groups of military veterans receiving care at a VA outpatient specialty clinic, 1 with subthreshold PTSD at pretreatment (n = 51) and the other with full, diagnostic PTSD (n = 483). Multilevel analysis revealed that both groups experienced a significant decrease in PTSD symptoms over the course of therapy (the full and subthreshold PTSD groups experienced an average decrease of 1.79 and 1.52 points, respectively, on the PTSD Checklist with each increment of time, which was coded from 0 at pretreatment to 13 at posttreatment). After controlling for pretreatment symptom severity, a between‐groups difference was not found. These results suggest that CPT is an effective form of treatment among military veterans, and that its effectiveness does not differ between subthreshold and threshold groups.