Stereotypes function to organize the social world, acting as cognitive shortcuts and preventing us from becoming overwhelmed by the complexity of the social information that we encounter on a daily basis (Weary et al., 2001). As part of this process, people make automatic judgments about individuals of certain sexes or races, simplifying social reality and minimizing effortful thoughtprocessing (Tajfel, 1969). Even in the absence of conscious endorsement, culturally available social stereotypes commonly affect our thoughts, feelings and behaviours (Bargh, Chen & Burrows, 1996). Indeed, some particularly insidious stereotypes appear to serve existential functions and to be formed largely in an attempt to rationalize, justify, or explain existing social hierarchies (eg. Jost & Banjii, 1994; Hoffman & Hurst, 1990). If we hope to be able to lessen the intensity and pervasiveness of such stereotypes, it is crucial that we begin to recognize the deeply-seated functions that such categorizations perform. The following paper, focusing on gender stereotypes in particular, examines 1) how complementary gender stereotypes perpetuate inequality; 2) how System Justification, Lay Epistemic and Terror Management theories account for the perpetuation of such stereotypes, particularly in times of uncertainty and stress; and 3) how an increased understanding of the exceedingly complex psychological processes involved in such labeling might enable us to find ways to diminish stereotyping and its pernicious effects.