Despite extensive EMI research worldwide, few studies focus on stakeholders' EMI experiences through the lens of epistemological stance. Informed by 'epistemic injustice', this study examines the epistemic nature of EMI policy by examining Bangladeshi students' language ideologies to understand whose languages, knowledge, and voices are (mis)recognised and (de)legitimised in an EMI programme. Drawing upon an ethnographic study, data were collected through classroom observations, semi-structured interviews and relevant policy documents at a university in Southwest China. The findings revealed that the implementation of EMI policy shaped and influenced Bangladeshi students' language ideologies of English monolingual ideology and native-speaker ideology, thus reinforcing and contributing to epistemic injustice. The results demonstrate the necessity to consider the epistemological nature of social (in)justice in policy formulation and implementation, and how it is manifested by shaping the language ideologies of micro-level stakeholders. The findings provide insights into understanding EMI policy from a social justice perspective with implications for decolonial EMI policymaking and curriculum. By identifying and challenging the dominance of English and Western epistemologies in EMI education, the study provides insight into developing and embracing more inclusive and diverse learning environments that better reflect the needs and perspectives of students from various linguistic and cultural backgrounds.