The population is aging in most industrialized nations around the world, and this trend is anticipated to continue well into the future. This demographic shift impacts the workforce in that the average age of workers is increasing, and the workplace is becoming more age diverse, meaning different generations of employees are working side by side now more than ever before. Increasing age diversity can be problematic if misguided age-related attitudes, biases, and behaviors lead to ageism—the stigmatization of, and discrimination against, people based on age. Evidence of the impact of ageism in the workplace is being observed in increasing age-related discrimination claims as well as increased time for older people to find employment. Workplace ageism manifests from cognitive, affective, and behavioral components. Age stereotypes are associated with the cognitive component, age-related prejudice is related to the affective component, and age discrimination is aligned with the behavioral component. There is an abundance of research identifying age-related stereotypes and it is thought that these stereotypes influence how workplace decisions are made. Age-related prejudice research indicates that older workers are generally viewed more negatively than younger workers which can result in lower performance appraisals or older workers’ receiving harsher consequences for lower performance. Finally, age-discrimination research has identified that older workers struggle to find employment, to receive training and development opportunities, and to advance their careers. Although the majority of research on workplace ageism has focused on older individuals, younger workers also face challenges related to their age and this is a line of research that needs further exploration. Nevertheless, the accumulating evidence supports claims that workplace ageism has wide-ranging effects on individuals, groups/teams, organizations, and society.