Borderline personality disorder (BPD) is a severe mental disorder that onsets during adolescence. Research examining sociocontextual differences in BPD presentation is limited and provides mixed results, highlighting the importance of further investigation and the evaluation of potential measure effects. This study assessed measurement invariance of two widely used adolescent measures (self-report-the Borderline Personality Features Scale for Children and semistructured interview-Childhood Interview of Borderline Personality Disorder) of BPD. Comparisons across inpatient psychiatric settings (n = 521 at a private inpatient; = 378 at a public inpatient) and across self-identified Hispanic/Latinx ( = 193), Black ( = 132), and White ( = 584) adolescents were conducted. Baseline models revealed inadequate model fit for a single-factor structure, requiring modifications to the intended structure of these measures. With these modifications, results identified partial scalar invariance across settings and racial/ethnic groups for both measures and full measurement invariance for the modified CI-BPD across settings. This study is the first to test whether these measures of BPD function differently based on an indicator of socioeconomic functioning and across racial/ethnic groups among inpatient adolescents. Results suggest that modifications to these measures should be explored further, which are discussed with the goal of achieving measures that can accurately assess and compare BPD severity in adolescents. (PsycInfo Database Record (c) 2025 APA, all rights reserved).