OBJECTIVE:Mindfulness forms the basis for multiple clinical interventions and has been induced in laboratory settings. However, few studies have examined the effects of dispositional or trait mindfulness. The purpose of this study was to investigate the relationship of trait mindfulness to laboratory stressor responding across fear-based anxiety disorder and non-anxious samples. We hypothesized that trait mindfulness would be associated with diminished stressor responding above and beyond the contribution of anxiety and depression-related variables, and to a greater extent in high anxiety than low anxiety individuals. METHODS: 90 participants, including 46 with anxiety disorders and 44 non-anxious controls, were assessed on hyperventilation and relaxation stressors. The relationship of trait mindfulness to stressor-related anxiety, negative affect, and duration was investigated in a hierarchical multiple regression model. RESULTS: Trait mindfulness predicted stressor responding in over 80% of measured outcomes, and predicted to a greater extent among high anxiety individuals in 50% of outcomes. CONCLUSIONS: Trait mindfulness was associated with diminished responses to laboratory stressors in clinically anxious and non-anxious samples. Implications for emotion regulation and clinical interventions are discussed.