Teacher supervision plays a pivotal role in the improvement of education system and the way in which teachers and student teachers perceive it. Consequently language teacher supervisors can utilize appropriate supervisory models to keep teachers update and promote them professionally. The present study investigated the role of language teacher supervisors in student teachers and in-service teachers’ professional development in Iran. To have a representative sample, some 210 EFL teachers practicing in the secondary schools and a total of 215EFL student teachers studying English at some Iranian state and Azad universities participated in the study. A 43-item questionnaire regarding EFL teachers’ attitudes about the impact of supervisory practice on their professional development with a format of a 5-point Likert-type was distributed among them. Also, ten percent of the participants were interviewed. Then the frequencies related to each item were calculated and a Chi-Square was used. Subsequently, qualitative data were transcribed. The results indicated that in-service and pre-service teachers have the same perceptions towards the role of their supervisors in their professional development. However, according to the findings it was concluded that the models of language teacher supervision in language teacher education are different from the models practiced in in-service classes where mostly traditional models are common.