The dimensional pathological personality trait model proposed in the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-5), Section III Criterion B, has shown promising results for its validity and utility in conceptualizing personality pathology. However, as its structural equivalence across sex is yet to be tested, the validity for the model across males and females remains uncertain. In the present article, we examined sex measurement invariance of the DSM-5 trait model in a large undergraduate sample using the Personality Inventory for DSM-5. A series of confirmatory and exploratory factor analyses suggested that, although the exact facet-domain relationships as specified in the DSM-5 were not observed, the facets generally organize into a model with five latent factors similar to those listed in the DSM-5 Section III Criterion B. Further, these five factors were fully measurement invariant across sex at the configural, metric, and scalar levels. Examination of the latent trait mean levels suggests that females tend to have higher scores on latent Negative Affectivity, whereas males tend to have higher scores on latent Antagonism, Detachment, Psychoticism, and Disinhibition. These results indicate that the DSM-5 Section III pathological personality trait model is fully structurally equivalent across sex, a property that is lacking in the traditional categorical model in Section II. This further validates the use of the dimensional DSM-5 trait model for personality disorder assessment and conceptualization in both research and clinical settings. (PsycINFO Database Record (c) 2019 APA, all rights reserved).