With the shifting dynamics within higher education, there is a stronger reliance and need for financial support in order to aid the institution's growth and financial health. One particular segment of their donor base that institutions will need to cultivate in order to respond to these dynamics is among their alumni. Simultaneously, while many institutions have made significant advancements for resources, services, and inclusion of lesbian, gay, bisexual, transgender, and/or queer/questioning (LGBTQ+) people, barriers to their academic, economic, social, and mental health still exist. Using student involvement, queer identity development, and identity-based alumni engagement theoretical models as guides, this study aimed to investigate the relationship between LGBTQ+ undergraduate student involvement experiences on alumni engagement in institutional advancement activities post-graduation. The overarching contribution of this study makes to how scholars and practitioners should understand the alumni engagement of LGBTQ+ people is that what they do during their undergraduate career informs what they do as alumni. This study begins to demonstrate how sense of belonging, validation, and identity saliency play consequential roles in these alumni's undergraduate experiences that relate to desirable outcomes of interest in terms of practices and behaviors of engaged alumni. This trio of considerations fits underneath the new umbrella terms "queer-salient undergraduate involvement and queer-salient alumni engagement". The concept of queer-salient undergraduate involvement and alumni engagement is the understanding of how one's queer identity shapes involvement during their undergraduate years or as alumni in terms of alumni engagement as defined as volunteering or philanthropic giving. Prior literature makes plain that LGBTQ+ identities are critical in the ways that not only queer and trans* students get involved during their undergraduate years, but also how the institution, and institutional actors, involve them during and after their undergraduate career. In better comprehending the relationship between student involvement and alumni engagement, higher education practitioners and scholars can understand how to better support and engage LGBTQ+ populations during their undergraduate years and post-graduation to foster mutually beneficial relationships. [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.]