Research on the factor structure of psychopathy has yielded mixed results, supporting anywhere from one to three factors. Additionally, most of this research has used all-male samples, and the possibility of structural invariance across gender has not been examined. Using a mixed-gender sample of 360 undergraduates, the factor structure of the Psychopathic Personality Inventory--Revised was examined using confirmatory factor analysis and multiple group analysis. One-, two-, and three-factor models were tested and compared with each other. When males and females were combined, none of the three models provided adequate fit to the data. Multiple group analyses revealed partial invariance across gender for all three models. Model comparison criteria supported use of both the one- and two-factor models, taking into account variable factor structure across gender. The importance of considering structural differences based on biological sex when assessing psychopathic traits is discussed. (Contains 1 note, 3 tables, and 3 figures.)