This study aimed at investigating job-related challenges faced by Iranian EFL junior and high school teachers during their professional jobs as English language teachers. To this end and to develop a valid questionnaire for investigating the Iranian EFL teacher challenges, researchers first asked a representative group of teachers for their views on the challenges they have confronted during their professional jobs. Then the data were classified into seven main challenges including textbooks, teachers, learners, social problems, spaces and educational facilities, educational systems, and social contexts. After developing the instrument, the participants who were 93 Iranian EFL junior and high school teachers were required to respond to open-ended items related to each classification. The findings demonstrated that Iranian EFL teachers have a wide range of challenges concerning their professional careers understanding of which can exert a great impact on EFL teaching and learning process. The results have different theoretical as well as practical implications for students, teachers, policymakers, learners, and curriculum developers.