The gender wage gap impacts millions of women throughout the US and world, with women in the US making on average 82 percent of men's salaries (US Census Bureau, 2018). In research libraries, a field dominated by women, this has historically been true as well, with men rising to top positions at a higher rate and making more money than women in the same positions. Over the decades following the implementation of Affirmative Action, the number of women in administrative positions in research libraries has increased dramatically. This article explores the issue of women's salaries in research libraries in five job tiers. The five job tiers group library positions based on power dynamic, with the first tier including positions that run academic libraries, through the fifth tier, which includes front-line positions. An analysis of data from the Association of Research Libraries from 1976 through 2016 demonstrates that, though women have made progress in obtaining higher-level positions, salary disparities continue to exist between men and women at all levels.