Recent initiatives in the empirically based classification of psychopathology, namely, the Hierarchical Taxonomy of Psychopathology (HiTOP), have made significant strides in addressing the limitations of traditional taxonomies (i.e., Diagnostic and Statistical Manual of Mental Disorders, International Classification of Diseases). The current study aimed to extend this work by helping to clarify the lower order structure of an understudied dimension of psychopathology-antagonism (i.e., HiTOP antagonistic externalizing spectrum)-a core feature of many externalizing disorders and related to important outcomes such as interpersonal problems, childhood conduct problems, and incarceration. We examined the hierarchical structure of several measures of antagonistic externalizing features across both self-report and clinical interview ratings for 2,279 community participants with a diverse range of personality pathology (~75% with a personality disorder) and antagonistic behaviors (~30% with intermittent explosive disorder). Exploratory structural equation modeling was used to account for the shared variance between variables within self-report and interview methods. Results revealed an optimal lower order structure consisting of six factors labeled Antisociality, Anger, Hostility, Narcissism, Mistrust, and Attention Seeking. Factor scores yielded expected relations with self-report and interview ratings of psychopathology, personality, and childhood trauma. Implications for future research in classification and treatment of psychopathology are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).