Examining English‐medium instruction implementation in Vietnamese higher education: Correlations between student self‐efficacy, language proficiency and academic performance

Abstract This study examines the relationship between English‐medium instruction (EMI), self‐efficacy development and English performance among Vietnamese undergraduate students. Using a sequential explanatory mixed‐methods design, the research investigated changes in self‐efficacy through EMI instruction and explored self‐efficacy as a predictor of English performance. Data were collected from 311 undergraduate students across three Vietnamese universities through self‐efficacy questionnaires, Test of English for International Communication tests and semi‐structured interviews. The findings revealed differential patterns of self‐efficacy development across language domains, with receptive skills showing more substantial improvements than productive skills. Listening self‐efficacy demonstrated the strongest enhancement ( d = 0.82), followed by reading ( d = 0.76), speaking ( d = 0.59) and writing ( d = 0.54). Multiple regression analyses established self‐efficacy as a significant predictor of English performance, explaining 43.2% of performance variance. The relationship between self‐efficacy and performance was moderated by disciplinary context and institutional support, with stronger correlations observed among students with regular access to academic support services. These findings contribute to theoretical understanding of self‐efficacy development in EMI contexts and provide practical implications for implementing effective language support systems in Vietnamese higher education institutions. The study suggests the need for discipline‐specific approaches to EMI implementation and targeted interventions to enhance student confidence in academic language tasks.