The current study evaluated the extent to which facets of trait mindfulness moderate the relationship between social anxiety schemas and responses to a social anxiety stressor task. We also evaluated whether specific trait mindfulness facets uniquely predicted state stressor responding and trait social anxiety symptoms, controlling for social anxiety schemas and other mindfulness facets. Participants’ (N = 235; 70.6% female) social anxiety schemas were assessed by a measure of early maladaptive schemas. Participants also engaged in a speech task, following which behavioral avoidance (speech time) and self-reported desired avoidance and state anxiety were assessed. Results were analyzed using structural equation modeling and indicated that mindfulness facets were not a significant moderator of the relation between schemas and behavioral avoidance. However, results suggested that specific mindfulness facets function as unique predictors of responses to a social anxiety stressor and trait anxiety symptoms, above and beyond social anxiety schemas and other facets of mindfulness. Interestingly, results indicated that the Describe facet of mindfulness was the most robust predictor of state stressor responding. Given their differential prediction of social anxiety symptoms, results highlight the importance of individually evaluating the unique components of mindfulness, as opposed to testing mindfulness as a unified construct.