Well-being is defined as individuals' subjective and global judgment whether the individual is experiencing the relative presence of positive emotions, the relative absence of negative emotions, and satisfaction with their life. This chapter addresses individuals' well-being at work, since work composes an important part of individuals' life experiences and has important effects on both employees' and organizations' effectiveness. For this purpose, this book chapter provides a comprehensive overview of well-being with respect to its predictors as well as its outcomes. More specifically, personality factors, job characteristics, and occupational stress are explored in terms of individual and organizational antecedents, whereas job satisfaction and work performance are utilized as outcomes of well-being. This chapter will be of interest to researchers, practitioners, and organizational consultants in providing a comprehensive guideline about the implications of well-being at work settings.