Models of worker flows have revitalized the idea of monopsony in the labor market. We apply such a model to gender differences. We argue that monopsonistic discrimination may be a substantial factor behind the overall gender wage gap, in particular with respect to differences arising between occupations and establishments. Using matched employer-employee data from Norway, we investigate the wage structure within and between establishments, and present novel evidence that the establishments' excess turnover of employees is sensitive to the wage premium of men, but not to the wage premium of women. Furthermore, we show that male turnover is more wage-elastic than female turnover.