Many higher education institutions (HEIs) in the United States have developed what is called post-entry language assessment (PELA) policies. The stated goal of PELA policies is to help admitted international students succeed academically by identifying those who are likely to struggle to meet the language demands of their degree programs and providing them with preparatory training to improve their academic English skills (Read, 2015a). Building on wider calls for socially conscious agenda for applied linguistics (Douglas Fir Group, 2016; Ortega, 2019) and language assessment (Deygers, 2019; Shohamy, 2017), this dissertation research examines an underexplored aspect in the study of PELA, namely, the value and social implication of stated PELA policies and the variety of actions and practices that shape them as de facto policies and further generate unintended consequences for multilingual international students. Amid the searing national conversation about social justice that our pandemic times have put on the spotlight, this dissertation contributes to the advancement of knowledge about critical questions such as: What social/cultural values underlie PELA? What happens in our education systems and the larger social contexts as a result of using PELA? The dissertation consists of three interrelated studies. In study 1, I conducted a document analysis and provided a bird's eye view of official PELA policies in 50 postgraduate education institutions in the U.S. The findings from study 1 allow me to offer an in-depth discussion of values, assumptions, and ideological underpinning of the stated policies as well as the ways in which PELA policies function in elevating or undermining the diversity, equity, and inclusion (DEI) efforts embraced by higher education systems. In study 2, I analyzed interviews with 9 policy actors - content faculty and ELI directors, and explored their policy interpretation and appropriation processes. The findings from study 2 reveal a wide spectrum of perspectives, beliefs, and language ideologies held by these stakeholders. Finally, in Study 3, I adopted a blend of critical discourse analysis and thematic analysis and analyzed 129 threaded posts from an online forum for Korean international graduate students. The findings from study 3 afford a window into the lived experiences of international graduate students seen through their own eyes, with particular emphasis on factors that interfere with their academic pursuits and well-being. Four main findings can be gleaned from the combined insights of the three studies. First, while PELA policies may bring instrumental benefits to students and HEIs, they can simultaneously help perpetuate deficit thinking and yield harmful material effects on multilingual international students' educational experiences. Second, policy actors utilize their agency and constantly draw on norms, their life experiences, and their expertise/knowledge, and engage a range of subject positions and identities to make sense of PELA policies imposed upon them, although their impact is often confined to their own spheres of influence (e.g., classroom) without more broadly challenging, much less transforming, the institutional sphere. Third, international students' perceived experiences and sense of vulnerabilities, intertwined with structural issues that permeate the host community (e.g., discrimination), shape their classroom and educational behaviors in stigmatizing ways. Fourth and lastly, stated policy rhetoric and felt realities reported by international students were often at odds with DEI values proclaimed by HEIs. Together, the dissertation research leads to the conclusion that in order to cultivate an inclusive environment, HEIs must take two steps: (1) engage in critical reflection about the assumptions and norms that drive many high-level decisions (e.g., policy formation, budget allocation) and (2) generate long-term, actionable plans to dismantle the systemic issues facing multilingual international students. I further discuss the study's implications for research, policy, and practice in the broader field of applied linguistics. [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.]