Insecure attachment is linked to mentalizing difficulties and psychopathology. The current study aimed to examine if failures in mentalization, as observed in the form of uncertainty about mental states, mediated the relationship between attachment styles and global psychopathology in a group of 812 adults (66.5% females) from the community. Participants completed measures on attachment styles, uncertainty about mental states, and clinical symptoms. The authors found that uncertainty about mental states was a partial mediator of the associations between attachment styles and psychopathology. Furthermore, the findings supported the role of secure attachment in protecting from mentalization failures and psychopathology; on the contrary, increased scores on attachment styles involving a negative view of the self (preoccupied and fearful attachment styles) predicted high levels of uncertainty about mental states and psychopathology. Accordingly, clinicians may wish to promote mentalizing abilities in individuals who display a negative view of the self embedded in their attachment styles.