In this article, we analyze the male-female earnings differential in the single most important sector of female employment, clerical and office work, for the period running from the 1880s to the 1970s. Clerical occupations currently provide jobs for one-third of all females engaged in market employment. Our analysis reveals that intraoccupational earnings differences between the sexes rather than differences in occupational structure have been the major factors underlying the male-female earnings gap in the clerical sector. This finding represents a major break with the conclusion reached in many earlier studies where researchers have argued that sex differences in occupational structure account for most of the sex differential in earnings (Cohen, 1971; Fuchs, 1971; Kreps, 1971; Sawhill, 1971). The empirical evidence presented here also suggests that the sex differential in earnings levels in the major clerical occupations has shown no substantial narrowing in recent decades. This result is surprising given the changing social climate of the post-World War II period. In recent decades we have seen a sharp upsurge in activity by feminist groups, pathbreaking civil rights legislation, increasing female labor force participation, increasing female career orientation, changes in sex roles, and other significant social changes. The results in this article suggest that up to now these social changes have not had a significant impact on the male-female earnings gap in the clerical sector.