This study explores staff and faculty's self-efficacy in advocating for transgender and nonbinary students within higher education. Through a multi-part self-efficacy assessment (n=249), this study specifically examines the general sense of self-efficacy staff and faculty have regarding transgender and nonbinary advocacy self-efficacy, differences between staff and faculty, and if advocacy self-efficacy varies for transgender and nonbinary students when compared to lesbian, gay, and bisexual students. The findings of this study indicate that staff and faculty generally have a high self-efficacy regarding working with transgender and nonbinary students. However, staff and faculty have a lower sense of self-efficacy regarding action-oriented types of advocacies. Overall, staff and faculty show minimal differences in their sense of self-efficacy. Finally, when compared to lesbian, gay, and bisexual students, staff and faculty have a lower sense of advocacy self-efficacy for transgender and nonbinary students. Preliminary analysis of influential factors indicates that one's role on campus as a staff member or faculty member and the number of LGBTQ+ cultural competency training that one has attended may have a more positive impact on self-efficacy than other factors, such as years of experience or frequency of interaction with students. Therefore, future research should further investigate cultural competency trainings that specifically target self-efficacy development as a possible educational intervention that may be effective at increasing staff and faculty advocacy self-efficacy for transgender and nonbinary students. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]