While existing literature has delved into the critical role of assessment in effective teaching and highlighted the complexities it introduces to classroom dynamics, there is relatively little discussion about assessment issues in English-medium instruction (EMI) settings. This Researching EAP Practice article presents the distinct tensions faced by two EMI teachers and their coping strategies at a top Chinese university amid ongoing EMI curriculum reform since 2020. Drawing on findings from classroom observation and semi-structured interviews, the paper identifies three sources of EMI assessment tensions: the interplay between language and content, the clash between teachers' sense of responsibility and students' language proficiency, and the conflict between teachers’ assessment beliefs and institutional policies and cultures. The coping strategies suggested are categorized into language-related, pedagogical, and compromising approaches. The paper concludes with thoughtful pedagogical recommendations for alleviating these tensions, emphasizing the necessity for collaborative efforts among various stakeholders involved in the educational process.