<p>This study addresses the academic language-related challenges undergraduate students face in English-medium instruction (EMI) programs and how these challenges vary across individual and contextual factors at a private Saudi university. Given the rapid expansion of EMI in Saudi higher education and the limited context-sensitive, mixed-methods research in this setting, the study responds to an urgent need for empirically grounded evidence to inform pedagogy and policy. Drawing on a mixed-methods design, the study combines survey data from 217 Saudi undergraduates with semi-structured interviews conducted with 16 students. The quantitative data were analyzed using descriptive statistics, t-tests, and ANOVA, while the qualitative data were examined through thematic analysis. Instrument validity was established through confirmatory factor analysis, and reliability was confirmed using Cronbach’s alpha coefficients. The findings reveal that students experience moderate levels of language-related challenge overall, with academic writing emerging as the most demanding skill. These findings directly answer the research questions by showing significant variation based on gender and prior EMI exposure, while no significant differences were found across disciplines or years of study. The study contributes to EMI research by providing context-sensitive, mixed-methods evidence from an under-researched Saudi private university context and by offering pedagogically relevant insights for targeted academic language support.</p>