Global and national education agendas are concerned with improving quality and equality of learning outcomes. This paper provides an analysis of the case of Vietnam, which is regarded as having high learning outcomes and less inequity in learning. But national data and international test outcomes may mask the hidden inequities that exist between minoritized groups and majority (Kinh) students. Drawing on data from qualitative videos and interviews of secondary teachers, we examine teachers' beliefs, curricular design and actions in ethnic minority and Kinh majority classrooms. We show that teachers hold different beliefs and engage in curricular design--or the use of hegemonic curriculum and instructional practices--that produce different learning outcomes for minoritized students compared to Kinh students. These findings suggest that policies need to focus on the social-cultural aspects of teaching in addition to the material and technical aspects.