Background: Borderline personality disorder (BPD) is characterized by emotion dysregulation; however, it is unclear whether this is restricted to negative emotional stimuli or to what degree this is specific to BPD. We investigated neural correlates of hypothesized increased emotional sensitivity and impaired emotion regulation in patients with BPD. Methods: During functional MRI (fMRI) scanning, patients with BPD, nonpatient controls and patients with cluster-C personality disorder completed an emotion regulation task, including negative, positive and erotic social pictures. Results: We included 55 patients with BPD, 42 nonpatient controls and 24 patients with cluster-C personality disorder in our analyses. Passive viewing of negative stimuli resulted in greater activity in the anterior insula, temporoparietal junction and dorsolateral prefrontal cortex in patients with BPD than in nonpatient controls. The increased activity in the anterior insula and temporoparietal junction was also present when patients with BPD viewed positive stimuli. During regulation of negative stimuli compared with passive viewing, nonpatient controls showed greater activity in the dorsal anterior cingulate cortex, dorsolateral prefrontal cortex, middle temporal gyrus and bilateral inferior parietal lobule. Patients with BPD did not show this increase in activity. Limitations: Findings cannot be generalized to men, and patients represented a heterogeneous group regarding comorbid diagnoses and medication. Conclusion: When looking at emotional stimuli, patients with BPD showed a unique pattern of activity, suggesting an increase in brain activity involved in emotion generation. In the case of negative stimuli this is accompanied by increased activity in regulation areas. In contrast, increase of regulation processes seems absent when patients with BPD are explicitly instructed to regulate. Results of diagnosis specificity support a dimensional rather than a dichotomous differentiation between BPD and cluster-C personality disorder regarding emotional sensitivity and emotional regulation of social stimuli.