Paranoia is common across the clinical and non-clinical spectrum. Cognitive behavioural therapy for psychosis currently yields modest results, warranting research into symptom-specific maintenance factors to improve outcomes. There is strong evidence of a relationship between insecure attachment and increased paranoia, but little is known about the mediating mechanisms. Emotion dysregulation is associated with both insecure attachment and paranoia, and a candidate causal mechanism. This study aimed to determine if emotion dysregulation mediates the association between attachment and paranoia. Sixty-two individuals with elevated paranoia were recruited from NHS services and community settings across the South of England. Mediation analyses were conducted on trait attachment, emotion regulation and paranoia variables, which were collected at one time point. As predicted, emotion dysregulation mediated the relationship between attachment avoidance and paranoia, and between attachment anxiety and paranoia. Emotion suppression did not mediate the relationship between attachment avoidance and paranoia, possibly due to power. Attachment avoidance correlated with deactivating emotion regulation strategies (e.g. lack of emotional awareness) and attachment anxiety correlated with hyperactivating emotion regulation strategies (e.g. impulse control difficulties). Both deactivating and hyperactivating strategies correlated with paranoia. Emotion dysregulation is not routinely targeted in cognitive behavioural therapy for psychosis. This study suggests that incorporating emotion regulation strategies in therapy may improve clinical outcomes. Experimental studies are now required to support a causal argument, and pilot intervention studies should investigate if emotion regulation skills development (aligned with attachment style) is effective in reducing non-clinical and clinical paranoia.