Unstable interpersonal relationships and fear of abandonment are core symptoms of borderline personality disorder (BPD) that often intensify during stress. Psychosocial stress, which includes components of social exclusion and increases cortisol secretion, enhances emotional empathy in healthy individuals. Women with BPD, on the contrary, react with reduced emotional empathy. The aim of the present study was to investigate the effects of perceived social exclusion without accompanying cortisol increase on empathy in women with BPD and healthy women. To induce social exclusion, we randomized 98 women with BPD and 98 healthy women to either an exclusion or an overinclusion (control) condition of Cyberball, a virtual ball game. Subsequently, participants underwent the Multifaceted Empathy Test (MET), which assesses cognitive and emotional empathy. There was no increase in cortisol release after Cyberball. Cognitive empathy did not differ between groups or conditions. Women with BPD reported lower emotional empathy for positive emotions (group by valence interaction), but not for negative emotions. Exploratory analyses suggested that this effect might be more pronounced after social exclusion. Our results confirm previous findings that cognitive empathy does not differ between women with BPD and healthy women and extend this evidence to social exclusion. Emotional empathy in women with BPD seems to be more sensitive to the effects of stress or ambiguous social situations. Specifically, emotional empathy seems to be reduced for positive emotions, and might further decline after social exclusion. Empathic reactions to emotional stimuli of different valences and to specific emotions should be further investigated.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00406-022-01535-0.