Research on the work-life interface does not specifically account for how individuals cognitively conceptualize their work and nonwork lives in terms of the differentiation between work and nonwork self-aspects. In addition, no cross-cultural research examines self-concept differentiation in conjunction with employee outcomes of presenteeism and engagement, pointing to a need to study these relationships cross-culturally. Results of the current study revealed cultural differences in self-concept differentiation, engagement, mental presenteeism, and physical presenteeism. Indian participants reported lower levels of differentiation and higher levels of engagement, mental presenteeism, and physical presenteeism than American participants. Nationality interacted with self-concept differentiation to predict mental presenteeism, physical presenteeism, and engagement. Among Indian participants, self-concept differentiation did not impact scores on the other variables. However, among American participants, those lower in differentiation reported greater engagement, lower mental presenteeism, and lower physical presenteeism. These results have important implications for the study of the work-life interface, and they provide evidence that engagement and presenteeism may be culturally contingent.