English-medium instruction (EMI) has been promoted in China’s mainland for over two decades, and its developmental landscape is complex. This article explores ideological tensions and how these tensions are created in the discourse of Chinese medical teachers and students in EMI courses. Drawing on the concept of tension-filled English, this article employs critical discursive psychology (CDP) to analyse ideological tensions in identity construction that emerged in semi-structured interviews with teachers and students about their imagined EMI courses. The analysis identifies two main ideological tensions between monolingual and bilingual approaches to EMI and between standard and practical orientations to English. By observing the interplay among different language ideologies in identity making, this study provides a valuable angle to understand the challenge-ridden experience of EMI teachers and students according to their own contextual needs and disciplinary practices. The findings suggest the importance of EMI stakeholders reflecting on how teaching and learning practices can enable learners (and teachers) to reflexively understand the role of English (and other languages) and leverage their bilingual repertoires for medical careers.