The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) recognizes a developmental perspective on personality pathology owing to its proposal to conceptualize personality pathology in terms of maladaptive personality traits. Previous research has found that the DSM-5 maladaptive traits and the five-factor model (FFM) for normative personality traits share common underlying dimensions. Although the DSM-5 generally assumes DSM-5 traits to be extreme versions of FFM traits, empirical evidence is scarce in adolescents. The present study therefore extended previous studies by comparing the Personality Inventory for DSM-5 and the Big Five Inventory-2 (BFI-2) in an adolescent sample (n = 353), using item response theory. Results indicated an underlying dimension for all domain pairs except for FFM Openness and Psychoticism. Consistent with the general assumption, IRT results demonstrated that Personality Inventory for DSM-5 scales generally provided more information than the BFI-2 scales at the upper levels of the latent dimension. The BFI-2 scales provided more information at the lower levels. For FFM Conscientiousness and Disinhibition, however, the BFI-2 scale provided more information for almost the entire range of the latent dimension. The findings indicate similarities in the DSM-5 conceptualization of personality pathology between adults and adolescents and at the same time identify important differences that need to be considered. (PsycInfo Database Record (c) 2021 APA, all rights reserved).