A body of work has developed over the last 20 years that explores facial emotion perception in Borderline Personality Disorder (BPD). We identified 25 behavioural and functional imaging studies that tested facial emotion processing differences between patients with BPD and healthy controls through a database literature search. Despite methodological differences there is consistent evidence supporting a negative response bias to neutral and ambiguous facial expressions in patients. Findings for negative emotions are mixed with evidence from individual studies of an enhanced sensitivity to fearful expressions and impaired facial emotion recognition of disgust, while meta-analysis revealed no significant recognition impairments between BPD and healthy controls for any negative emotion. Mentalizing studies indicate that BPD patients are accurate at attributing mental states to complex social stimuli. Functional neuroimaging data suggest that the underlying neural substrate involves hyperactivation in the amygdala to affective facial stimuli, and altered activation in the anterior cingulate, inferior frontal gyrus and the superior temporal sulcus particularly during social emotion processing tasks. Future studies must address methodological inconsistencies, particularly variations in patients’ key clinical characteristics and in the testing paradigms deployed.