The aim of this chapter is to give an overview of the academic debate on age, ethnicity, and class, in particular their intersectionalities within organizations. Although the social categories of age and ethnicity are well studied by diversity scholars, literature on the combined effects of these dimensions for individuals and organizations is still scarce. This holds even more for the category of class. While there exist scattered analyses of class-related issues within the field of diversity studies, up to now there is no analysis that considers the interplay of class with both age and ethnicity. Against this background the chapter examines the age–ethnicity–class intersectionality by concentrating on the three dyadic relationships: age–ethnicity, age–class, and class–ethnicity. It provides a summary of previous research findings, a critical reflection of thinking that relies on social categories, and a discussion of avenues for future research.