This study examines the causes and consequences of gender segregation in the workplace. It draws on theories in cognitive social psychology, institutional organizational theory, and labor economics to construct hypotheses about the conditions affecting individuals, jobs, organizations, and their environments. Multiple data sources will be examined, including a unique data set made up of class action suits relating to gender discrimination. Statistical models are used to assess the following questions: 1) why the gender composition of jobs varies within and across organizations, 2) the mechanisms through which the gender composition of jobs influence earnings and career advancement, and 3) the relationship among gender, job segregation, and work effort. %%% This research explores the ways organizational structures and processes shape labor market outcomes for men and women. It will search new empirical sources for evidence to contribute to the continuing debate on gender segregation in the workplace. It will also clarify the impact of Equal Opportunity legislation on labor market dynamics.