The study investigated Post-Basic education teachers' beliefs and practices of learner autonomy. In addition, it examined the influence of the teachers' years of teaching experience on their beliefs and practices. It also investigated the challenges of promoting learner autonomy in the Omani context as perceived by the teachers. Two instruments were used to answer the research questions: a questionnaire and a classroom observation checklist. The study was conducted with grade 11 and grade 12 female English teachers in Dhofar governorate in the academic year 2014/2015. The sample for the questionnaire of the study consisted of 80 teachers (95% of the population). The sample for the observation consisted of 28 teachers who were chosen randomly. Each teacher was observed 3 times. The results of the questionnaire were presented using the means and the standard deviations and the results of the checklist were presented using the frequencies. The study findings indicated that the teachers strongly believe in the positive effect of learner autonomy in language learning and in the important role the teacher has in promoting learner autonomy. They also strongly believe in the effectiveness of certain practices in promoting learner autonomy such as social interaction, developing students' mental attributes, increasing students' motivation and involving students in making decisions. The findings of the observations revealed that there is a consistency between the teachers' beliefs and practices except for the practices that are related to involving students in decision-making as the teachers do not practice them often in their teaching. Another major finding is that there is no significant difference at the 0.05 level between the inexperienced and experienced teacher' beliefs and practices of learner autonomy. As for the challenges of promoting learner autonomy, the teachers believe that students' preference of the teacher-centered approach is the most relevant challenge to the Omani context. In light of the findings, implications for in-class teaching and recommendations for policy makers and future research are given.