As English-medium instruction (EMI) programs have expanded rapidly in Vietnam as a result of educational globalisation, more research is needed in this field. This study aims to promote EMI lecturers’ professional development and enhance teaching quality by identifying the needs of content lecturers in Vietnamese higher education, in order to gain a more comprehensive insight into appropriate support and policy development. Data were collected via questionnaires distributed to EMI lecturers (n=33) and in-depth interviews with six participants. The findings show that EMI lecturers required professional development support, particularly in improving their pedagogical competencies and English language proficiency. They also expressed a desire for collaboration with colleagues. In addition, this study identified lecturers' specific needs for institutional support, with particular emphasis on teaching materials and resources. These insights contribute to the existing literature and provide helpful suggestions for supporting EMI lecturers in similar settings.