Learner autonomy is now regarded as a desirable objective in language teaching. The movement towards learner-centered approaches has resulted in more emphasis on the benefits of learner autonomy in the success of language education. The objective of the study was to identify ELT teachers’ strategies and challenges in promoting EFL high school students’ autonomy in vocabulary learning. A qualitative interview was undertaken to seek the results. The findings of this study revealed that English language teachers frequently promoted autonomous learners in their classrooms. They usually implemented different teaching strategies, which can be categorized into three groups including involving students in a student-centered atmosphere; playing various roles in the classroom; and equipping students with the strategies to learn vocabulary. Additionally, the results demonstrated that teachers faced challenges such as learners' lack of independent learning abilities, rules and regulations implemented in schools, and teachers' lack of fundamental ways to promote autonomous learning. Teachers, students, school stakeholders, and curriculum designers can all benefit from the findings. Finally, it is hoped that the proposed pedagogical implications will contribute to the innovation of promoting learner autonomy in vocabulary learning in the context of high school in the Mekong Delta of Vietnam.

Keywords: Challenges, Learner Autonomy, Strategies, Vocabulary Learning.