The theory of compensating differentials suggests that workers with flexible schedules will earn less than other workers. Some authors have also contended that the concentration of women in jobs with flexible hours explains a significant part of the gender pay gap. This paper uses data from the US subset of the Comparative Project in Class Analysis to test these hypotheses. These data first indicate that, contrary to popular wisdom, women workers do not have more flexible schedules than men. Second, the really striking differential is by race: black workers have much more rigid schedules than white workers. Third, workers with more authority at the workplace typically have more flexibility than subordinate workers. Finally, the data show that any compensating differentials for flexible hours are small and are offset by returns to workplace authority.