Faculty gender ratios vary considerably across institutions, and past research has shown that certain characteristics of institutions have a significant effect on these gender ratios. Understanding the drivers of faculty gender ratio variation is important since the concentration of women in particular types of institutions contributes to gender differences in earnings, career patterns, and employment outcomes. This study tested the hypothesis, drawn from theories of organizational behavior, that gender ratios of assistant professors are influenced by employers' discriminatory preferences, the gendered composition of the student body, and women's preferences for employment in teaching versus research universities. In addition, it was hypothesized that public institutions and institutions located in highly populated areas would have a greater proportion of female assistant professors. The explanatory variables suggested by the hypothesis were examined using cross-sectional data for 233 research and doctoral universities from two separate years, and a fixed-effects analysis was used to obtain unbiased estimates. Results support all of the hypotheses except for the preference of women for employment in teaching universities. This thesis also attempts to explain the variation in faculty gender ratios across economics departments. It was hypothesized that the departmental model would be more accurate than the institutional model since hiring decisions are made at the departmental level. The results, however, do not support this hypothesis. The implications for future studies of interorganizational variation in faculty gender ratios are discussed. (Contains 13 references.) (Author/SLD)