The increase in international graduate students (IGSs) in the United States in recent years has created additional linguistic and cultural diversity in graduate programs, thus, spotlighting the existence of these students' unmet challenges. Although much research has been conducted on the experiences of international students in U.S. higher education contexts, very little research has focused on IGSs' transition experiences to and through academic and professional university programs by way of pathway language support programs. Applying activity theory, I designed and conducted this case study with explanatory sequential mixed methods to investigate IGSs' experiences as they transitioned into and through a university Master of Public Health (MPH) program. To reach a broader view of student challenges, I surveyed the perspectives of MPH faculty and administrators, the IGSs, and the university's English language pathway program faculty and staff. Using the survey results and in an effort to dig deeper into the themes that arose in those surveys, I constructed protocols for semi-structured interviews of each of these three groups. Additionally, I gathered background information and artifacts to provide a richer understanding of all stakeholder group contexts. Results indicated mismatches in knowledge and expectations of stakeholders in those three groups, specifically in IGSs' understanding of the learning objectives and assessment styles practiced in the MPH. Implications include ways in which university activity systems (MPH, pathway programs, and students) can adjust to reduce international students' challenges in U.S. graduate programs. [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.]