In this paper, we investigate the mechanism by which the femaleness of occupations has a negative effect on women's wages. We relate US/Canada differences in labor market institutions, the returns to skills and other dimensions of the wage structure, such as occupational rents, to corresponding differences in the rewards to female jobs. Our analysis, which uses US data from the CPS-ORG for 1988 and Canadian data from the 1988 LMAS, uncovers intriguing US/Canada differences in the effect of occupational gender composition on women's wages. The estimated effect for Canadian women is generally small and not statistically significant, while estimates for American women are relatively large and comparable to the evidence in previous studies. Relating these differences to cross-country variation in other wage determinants reveals that higher rates of unionization, and the higher occupation wage effects for certain public good sector jobs such as educational services, work to the advantage of Canadian women. We also find that the relatively higher pay of integrated jobs in the United States helps account for the larger negative effect of gender composition on women's wages in this country.