Objectives: There is evidence of associations between insecure attachment and paranoia, but we do not yet fully understand the mediating mechanisms. Attachment theory emphasizes differential relatedness of insecure attachment dimensions (i.e., anxiety vs. avoidance) with specific emotion regulation styles (ER). We tested whether the associations between attachment anxiety versus avoidance and paranoia were mediated specifically by hyperactivating (i.e., the use of emotion-amplifying strategies: self-blame, rumination, catastrophization) versus blaming others ER, respectively. In addition, we explored whether self-blame versus blaming others ER differentially mediated the associations between attachment anxiety versus avoidance and paranoia. Method: We included 60 patients with psychosis and 40 healthy controls (HCs) with whom we conducted standardized diagnostic interviews. We assessed paranoia, attachment, and ER via questionnaires. A structural equation mediation model including attachment anxiety and avoidance (predictor), the ER styles (mediators), and paranoia (outcome) was calculated. Results: Compared with HCs, patients exhibited significantly more attachment anxiety and avoidance, and used more hyperactivating ER as well as strategies of blaming others. We found a significant indirect effect between attachment anxiety and paranoia via hyperactivating ER in patients with psychosis. However, no significant indirect effects involving blaming others or self-blame in any of the groups were found. Conclusions: Our study provides a starting point for further investigation of how paranoid delusions in psychosis could emerge from insecure attachment via ER. This might inspire further research into attachment theories of ER in paranoia. In the long term, this could provide a basis to develop interpersonally oriented interventions for this target group. Practitioner points: In individuals with psychosis, there appears to be an attachment-specific emotion regulation (ER) pathway from attachment anxiety via hyperactivating ER to paranoia. Blaming others did not explain the significant association between attachment avoidance and paranoia. Attachment-specific therapeutic approaches to paranoia, that focus on hyperactivating ER, could be a valid way to ameliorate paranoid delusions.