This study investigates faculty gender pay equity in higher education. Using data from the 2004 National Study of Postsecondary Faculty and drawing on human capital theory, structural theory, and the theory of comparable worth, this study uses cross-classified random effects modeling to explore what factors may be contributing to the pay differential between male and female faculty. Pay gaps between male and female faculty are explored by principal activity, discipline type, and institution type. The effect of the proportion of female faculty in disciplines and institutions on faculty salary is also examined. This study found that even after controlling for several factors related to human capital, demographic and structural characteristics, female faculty members earn approximately 2.8% to 4.5% less than male faculty. The results also suggest that salary differentials differ by institution type. As compared with Masters institutions, the gender pay gap is larger in Doctoral institutions and smaller in Associates institutions. Significant salary differentials were also found by principal activity (teaching or research). Finally, this study provides some support for the theory of comparable worth, suggesting that higher proportions of female faculty in disciplines are associated with lower salaries in those disciplines. Results are considered in light of existing legislation, discussing whether legitimate, legal factors or illegitimate factors, may be affecting faculty salary. This study raises important implications for those seeking to understand pay equity issues and develop informed pay policies and practices. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]