Empirical evidence documents disparities in the diagnosis of severe forms of psychopathology among racial/ethnic minority persons. However, research on diagnostic differences in personality disorders is equivocal: Some suggest higher prevalence of personality disorders among racial/ethnic minority persons, whereas other results suggest the opposite. The goal of the current study was to investigate (a) differences in the diagnosis of borderline personality disorder (BPD) in a mostly cisgender, heterosexual sample among racial/ethnic minority patients compared with non-Hispanic White patients and (b) whether any observed differences were attributable to differences in underlying maladaptive personality domains. Using data from partial hospital patients (N = 2,657), we found few differences in the diagnosis of BPD based on racial/ethnic group membership. We also conducted measurement invariance analyses of the Personality Inventory for DSM-5-Brief Form (PID-5-BF), finding evidence of invariance across White and non-White participants in these data. Any instances of diagnostic disparity were explained by group differences in maladaptive personality domains. These results provide context to the extant literature documenting mixed results about racial/ethnic differences in prevalence of personality disorders. In addition, they suggest relative specificity in BPD diagnostic bias related to sexual minority populations.