BACKGROUND/OBJECTIVES: Trait mindfulness (TM) may protect against post-trauma mental health ailments and related impairment. Few studies have evaluated this association in the context of collective traumas using representative samples or longitudinal designs. DESIGN/METHOD: We explored relationships between TM and collective trauma-related outcomes in a prospective, representative, probability-based sample of 1846 U.S. Gulf Coast residents repeatedly exposed to catastrophic hurricanes, assessed twice during the COVID-19 outbreak (Wave 1: 5/14/20-5/27/20; Wave 2: 12/21/21-1/11/22). Generalized estimating equations examined longitudinal relationships between TM, COVID-19-related fear/worry, hurricane-related fear/worry, global distress, and functional impairment; ordinary least squares regression analyses examined the cross-sectional association between TM and COVID-19-related posttraumatic stress symptoms (PTSS) at Wave 1. Event-related stressor exposure was explored as a moderator. RESULTS: In covariate-adjusted models including pre-event mental health ailments and demographics, TM was negatively associated with COVID-19-related fear/worry, hurricane-related fear/worry, global distress, and functional impairment over time; in cross-sectional analyses, TM was negatively associated with COVID-19-related PTSS. TM moderated the relationship between COVID-19 secondary stressor exposure (e.g., lost job/wages) and both global distress and functional impairment over time. CONCLUSIONS: Results suggest TM may buffer adverse psychosocial outcomes following collective trauma, with some evidence TM may protect against negative effects of secondary stressor exposure.