Transgender and/or Nonbinary populations in the United States experience significant rates of harassment, discrimination, victimization, and psychological distress in nearly all aspects of life due to systemic stigmatization against those who violate societal gender norms. Such social disparities are often enacted through the environmental and interpersonal interactions of Transgender and/or Nonbinary individuals beginning in their formative years and throughout their lifespan. Tangible consequences from these biased interactions can be seen in their systemic economic stratification due to employment insecurity, which hampers their ability to participate in mainstream society and perpetuates their marginalization. Given the relationship between postsecondary degree attainment and the economic and employment security of Transgender and/or Nonbinary individuals, the focus of this study was to uncover the ways in which they perceive their environmental and/or interpersonal interaction factors influencing their postsecondary academic selections. Drawing from Spade's (2015) Critical Trans Politics, Bronfenbrenner and Morris's (2006) Process-Person-Context-Time Model, and Museus's (2014) Culturally Engaging Campus Environments Model (CECE Model) of College Success, a participatory-social justice, narrative inquiry design was used to answer this study's research questions. Potential implications from this study on the U.S. educational system and the experiences and life trajectories of Transgender and/or Nonbinary undergraduates are discussed. [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.]