This doctoral thesis investigated Vietnamese teachers' understanding and application of learner autonomy in their teaching practices. A mixed methods approach was used, including a survey of teachers and case studies of four teachers through interviews, observations, and stimulated recall interviews. The study found that teachers generally lacked understanding of learner autonomy and there was alignment between their beliefs and practices, resulting in little evidence of fostering learner autonomy. The findings provide insights into learner autonomy in Vietnam to inform teachers and policymakers.