Sociological literature has not paid the same attention to the educational attainment of lesbian, gay, and bisexual (LGB) persons, despite their status as a socially marginalized group. Through the application of sociological methods and theories, my dissertation argues that sexual identity's effect on educational attainment is "conditional". That is, determining whether sexual minorities are advantaged or disadvantaged educationally depends not only on their sexuality, but also on the social context in which they are nested. This work builds upon educational scholars' investigations of LGB student experiences to apply the same sociological inquiry used to determine other minority groups' educational attainment to sexual minorities. The second chapter of this work investigates the relationship between sexuality and educational attainment. Using the National Longitudinal Survey of Adolescent Health (Add Health), I run logistic regressions on respondents' likelihood of having a bachelor's degree. I use these results to predict probabilities of completing college for heterosexual men, heterosexual women, sexual minority men, and sexual minority women. Results show that education differentials as a function of sexuality are gender-dependent. LGB men are more likely to have a college degree than heterosexual men, and their educational attainment patterns mirror those of heterosexual women. LGB women, however, are the group least likely to have a bachelor's degree, indicating that their educational attainment patterns parallel heterosexual men's. Most studies of the interaction between lesbian, gay, bisexual, and transgender (LGBT) persons and the American college campus environment have been confined to the micro-level. However, little is known about factors at the institutional level that could affect the campus climate. In the third chapter, I use social closure theory to determine the link between institutional factors and a school's climate toward sexual minorities. Results indicate that a higher percentage of women, a more liberal political milieu, and a lower student-to-faculty ratio are associated with a more positive climate for LGBT persons, suggesting that macro-level factors exert an influence. Sexual minorities' education levels may differ from those of heterosexuals, but it is currently unknown how these differences manifest themselves--or if these differences are universal for all sexual minorities. The fourth chapter uses individual interviews with twenty-two lesbian, gay, and bisexual (LGB) respondents indicate that social support may explain the difference in educational trajectories both within the LGB community and between LGB persons and heterosexuals. LGB respondents who were classified as Drop-Outs--those that did not complete a bachelor's degree without interruption - were more likely to indicate a lack of supportive significant others. On the other hand, respondents classified as Graduates were more likely to have family, faculty, and friends who were supportive as they were out on campus - or delayed their coming out until after college. [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.]