This study examined the relationship between Machiavellianism and Organizational Citizenship Behavior. The research adopted the philosophy of positivism, the deductive approach, and the method of quantitative analysis as the research methodology. Based on established measurement scales, a questionnaire-based deductive approach was used to collect data from a quota sample of 379 employees from Mansoura University. The proposed model and hypotheses were analyzed using the structural equation modelling employing the PLS-SEM. The results indicated that Machiavellianism is negatively related to Organizational Citizenship Behavior and also showed that Machiavellianism is negatively related to Organizational Citizenship Behavior dimensions (Obedience, Loyalty, and Participation). Theoretical and practical implications as well as limitations and venues for future research are presented.