Individuals with borderline personality disorder (BPD) may experience distressing auditory hallucinations, phenomenologically similar to those seen in psychosis. However, access to effective intervention is limited. The cognitive model of auditory hallucinations highlights the role of appraisals in maintaining distress. Cognitive behavioural therapy (CBT) that targets such beliefs has shown efficacy in psychosis. This study examined appraisals about voices in individuals with psychosis and those with BPD to establish whether CBT for voices might have clinical utility for those with BPD.