Borderline personality disorder (BPD) is characterized by more frequent and more intense negative emotions and less frequent positive emotions in daily life than healthy controls (HC) experience, but there is limited empirical evidence regarding whether this is a transdiagnostic or disorder-specific finding and which specific emotions are especially distressing in BPD. We assessed participants’ current emotions and distress every 15 min over a 24-h period using e-diaries to investigate the frequency, intensity, and the associated distress of specific emotions. To test the disorder specificity, we used multilevel modeling to compare 43 female patients with BPD, 28 patients with posttraumatic stress disorder (PTSD), 20 patients with bulimia nervosa (BN), and 28 HC. Patients with BPD exhibited anger more frequently than any of the clinical or healthy control groups, demonstrating specificity. The quality of anger accounted for additional distress beyond the pure emotional intensity. In patients with BPD, joy was associated with reduced distress, which was not the case in HC or PTSD. However, the majority of the comparisons (anxiety, sadness, shame, disgust, jealousy, guilt, interest) revealed transdiagnostic patterns. ... mehrThe distress-enhancing or distress-reducing effects of anger and joy might represent an important part of affective dysregulation in BPD.