The diagnostic category of borderline personality disorder (BPD) has come under increasing criticism in recent years. In this paper, we analyze the role and impact of epistemic injustice, specifically testimonial injustice, in relation to the diagnosis of BPD. We first offer a critical sociological and historical account, detailing and expanding a range of arguments that BPD is problematic nosologically. We then turn to explore the epistemic injustices that can result from a BPD diagnosis, showing how they can lead to experiences (...) of testimonial injustice which impede patient engagement in meaning-making activities, thereby undermining standard therapeutic goals. We conclude by showing how our arguments bolster ongoing efforts to replace the diagnostic category of BPD with alternatives such as complex post-traumatic stress disorder. (shrink)