Learner autonomy has become a hot topic in the research of foreign language education. However, it is the most difficult question to define learner autonomy and any answer to it is likely to be subjective. On the basis of expounding upon the different definitions concerning the research on autonomy in language teaching and learning, the focus of the present paper is on the teacher’s roles in fostering learner autonomy. The roles that teachers are expected to play from the theoretical and empirical backgrounds are reviewed and the future research trend is explicated based on it.