Employee well-being is paramount in today’s organizations and has received a lot of attention from researchers in the field of industrial and organizational (I-O) psychology. In the light of globalization, researchers have started to investigate the cross-national generalizability of prevailing models of employee well-being. In the last two decades, the construct of positivity has been studied in the area of subjective well-being and I-O psychology, and might play an important role in cross-national investigations of employee well-being. This thesis investigates working conditions, employee well-being, and positivity across nations. This research is important because it can expand our theoretical knowledge of employee affect, behavior, and cognition, and increase our understanding of effective human resource management in multinational organizations. Archival data from the sixth European Working Conditions Survey (EWCS) and indicators of positivity reported in prior literature were used. The EWCS examined working conditions in European countries with the goal of contributing to policy and improving work quality in the European Union. Prior to all analyses, non-salary individuals were excluded from the dataset. Moreover, countries without positivity scores were excluded from the dataset. The final dataset included 15,821 employees in 14 countries. Countries’ sample sizes ranged from 638 in Greece to 2,769 in Spain. Working conditions were measured as job demands, using five items, and job resources, using seven items. Employee well-being was measured as exhaustion, using four items, work engagement, using three items, and job satisfaction, using four items. Multilevel regression analyses suggested that individual-level job demands and job resources related positively to exhaustion and work engagement. Furthermore, multilevel regression analyses indicated that nation-level positivity did not relate to individual-level work engagement or job satisfaction. Examinations of the mechanism of relationships between nation-level positivity and individual-level employee well-being outcomes were not appropriate because of non-significant direct effects. Additional multilevel regression analyses suggested that nation-level positivity moderated the individual-level relationship between job demands and exhaustion, but not job resources and work engagement. Yet, the nature of the significant interaction was opposite to the prediction. Implications of the findings for research and practice, and limitations of this thesis are discussed.