The present study aimed to investigate the mediating role of mentalization, epistemic trust, mistrust, and credulity in the relationship between narcissistic traits (vulnerable and grandiose) and depression. A correlational design with path analysis was employed. A convenience sample of 304 adults completed Beck Depression Inventory-II (Beck et al., 1996), Short Form of the Five-Factor Narcissism Inventory (Sherman et al., 2015), The Mentalization Scale (Dimitrijević et al., 2018) and Epistemic Trust, Mistrust, and Credulity Questionnaire (Campbell et al., 2021). The results revealed that both dimensions of narcissism had a significant positive indirect effect on depression through reduced mentalizing capacity and increased epistemic mistrust. However, epistemic trust played a significant mediating role only in the path between vulnerable narcissism and depression. The indirect paths through epistemic credulity were also not significant. Also, the direct effect of grandiose narcissism on depression was negative, but the total effect was positive through indirect paths. These findings highlight the distinct mediating mechanisms of narcissism dimensions and underscore the importance of capacities for social information processing in understanding depressive symptoms. The results may inform the development of preventive, psychoeducational, or therapeutic programs focused on enhancing mentalization and restoring epistemic trust in individuals with narcissistic traits.