This article focuses attention on research examining workplace discrimination against employees from marginalized groups. We particularly consider the experiences of seven different groups of marginalized individuals, some of which have legal protection and some of which do not but all of whom we feel have been overlooked by the field of industrial–organizational (I–O) psychology. We briefly describe the importance of studying each group and then delineate the brief amount of research that has been conducted. Finally, we make recommendations for I–O psychologists in terms of research and advocacy. Overall, we argue that I–O psychologists are missing an opportunity to be at the forefront of understanding and instigating changes that would result in maximizing the fairness and optimization of these often forgotten employees and their experiences in the workplace.