Using a micro-sociological lens, we develop a theoretical framework that explains how social class distinctions are sustained within organizations. In particular, we introduce the concept of "class work" and explicate the cognitions and practices that members of different classes engage in when they come in contact with each other in cross-class encounters. We also elucidate how class work perpetuates inequality, and the consequences of class work on organizations and those at the lower end of the organizational hierarchy. By examining micro-level interactions and how they become institutionalized within organizations as prevailing rules and practices, we contribute to both institution theory and the sociology of social class differences. We encourage future research on social class and discuss some of the challenges that inhere in conducting it.