The current investigation evaluated (1) the incremental predictive validity of non-judgmental acceptance in terms of alcohol use coping motives and (2) the mediating role of non-judgmental acceptance in the association between posttraumatic stress symptom severity and alcohol use coping motives. Participants included 153 (79 women) adults who reported exposure to at least one DSM-IV PTSD Criterion A traumatic life event and alcohol use in the past month. Non-judgmental acceptance emerged as a significant incremental predictor of alcohol use coping motives. Furthermore, non-judgmental acceptance partially mediated the association between posttraumatic stress symptom severity and alcohol use coping motives. Theoretical and clinical implications of the findings are discussed with regard to better understanding the co-occurrence of posttraumatic stress and alcohol use disorders.