Childhood maltreatment increases risk for Posttraumatic Stress Disorder (PTSD). Maladaptive patterns of attention to emotionally salient stimuli warrant examination as possible mediators of the relationship between childhood maltreatment and PTSD. It remains unclear whether persistent attentional biases are differentially apparent in adults who were maltreated as children and either did or did not develop later PTSD symptomatology. The present study examined associations among attention bias, childhood maltreatment, and PTSD in adults. We tested the hypothesis that attentional bias for emotional cues (angry faces, happy faces), measured using the Dot Probe Task, would significantly mediate associations between childhood maltreatment and adult PTSD symptoms in a sample of 161 adults with and without childhood maltreatment histories and/or current PTSD symptoms. We found that attention bias toward happy faces partially mediated the relationship between childhood maltreatment and PTSD avoidance and numbing symptoms.