The current study examined relationships between psychopathy factor severity and individual differences in reinforcement sensitivity theory factors. Phase 1 examined relationships between factors from the Reinforcement Sensitivity Theory of Personality Questionnaire (RST-PQ) and the two-factor model of psychopathy using the Levenson Self-Report Psychopathy Scale (LSRP) in 2914 undergraduate students (63% women). Multigroup observed variable path analyses revealed unique associations between RST-PQ factors and the two factors of psychopathy. Also, small differences in relationship strength across biological sex were observed. Phase 2 examined the two factors of psychopathy in relation to hedonic ratings from the behavioral Sweet Taste Test (STT), along with self-report measures of trait pleasure, in a subset of participants (n = 93; 66% women). Analyses revealed robust sex interactions in relationships between STT ratings and the two psychopathy factors. Men with greater secondary psychopathy severity predicted a reduced slope of liking ratings to increasing concentrations of sucrose, while women showed a positive hedonic slope for secondary and a negative hedonic slope for primary psychopathy. Future research should include analyses for possible moderation of sex and incorporate menstrual cycle status in women when examining measures collected in the laboratory.