As part of a large-scale study, the current study explored the barriers perceived by Iranian EFL teachers to impede their professional development. To this end, 200 EFL teachers teaching at various private foreign language institutes participated in the study. The study enjoyed a mixed-method design. That is, first, a semi-structured interview was conducted with 50 participants of the study on the basis of which the barriers to teachers‟ PD questionnaire (BTPDQ) was developed and validated. The results of the interview content analysis and the findings of the descriptive statistics of BTPDQ revealed the barriers were attributed to three major factors including „teachers themselves‟ (e.g., lack of motivation, lack of teamwork spirit, etc.), „managers of the language institutes‟ (e.g., institutes‟ not having organized plans for PD, low payments, etc.), and „educational policy-makers‟ (e.g., curriculum developers‟ top-to-down managerial behavior, etc.). The findings might prove fruitful and innovative for the managers of foreign language education centers, teachers, and policy makers. Foreign language education policy makers, curriculum developers and syllabus designers are thus suggested to plan such effective and durable PD activities as teacher study groups, peer observation, online teacher PD methods and socialmedia- based programs in order to interest and involve EFL teachers in up-todate PD activities.
