In the era of the globalization of the English language, Kazakhstan has strategically implemented English as a Medium of Instruction (EMI) in higher education. Accordingly, the aim of this study was to explore teachers' and students' perceptions of their EMI experiences, focusing on the interplay between language management (LM), language practices (LP) and language ideology (LI) (Spolsky, 2004). Thus, a qualitative case study design was employed wherein four teachers and six undergraduate students from one Department of Natural Sciences were interviewed. Moreover, information from the official website and policy documents of the university were used for document analysis of its EMI policy. The findings revealed that participants had a positive LI towards EMI as this is helpful for language development, although many of them encountered challenges during LP due to their low mastery of English. The university's LM system was unsuitable as administrators neglected to address the participants' linguistic difficulties related to EMI which led to the use of the translanguaging method for comprehension purposes during LP activities. The participants also reported that continuing LP in EMI and teachers' emotional support contributed to students' language improvement. Ultimately, this study suggests that administrators improve the quality assurance of the EMI policy.