According to the Biosocial theory, Borderline Personality Disorder (BPD) is developed by a biological predisposition to hyperarousal and hyperreactivity combined with an invalidating environment. Although widely supported by subjective measures, the impaired insight present in BPD may skew results, and thus psychophysiological measures have been suggested as an alternative method of examining possible biological differences in BPD. The current review aimed to critically assess psychophysiological research of BPD by electronic searching of relevant databases, with 22 articles meeting inclusion criteria. Results showed that in contrast to the hyperarousal proposed in the Biosocial theory, BPD was associated with hypoarousal and hyporeactivity to non-emotionally valenced stimuli. However, there was also evidence of BPD hyperreactivity towards negatively valenced stimuli, and impaired habituation during stressor tasks. As current psychophysiological results were inconsistent, it has been postulated that there may be possible subtypes of BPD. Further, evolutionary-based theories do not appear to adequately explain the complexity of emotion dysregulation in BPD, thus the Emotional Coherence theory has been proposed as an alternate method of conceptualising the role of psychophysiology in BPD. From the lack of clear or consistent findings, further research in the area appears necessary to determine the role of psychophysiology in BPD.