This study was an endeavor to analyze how English as a foreign language (EFL) teachers at Iranian senior high schools perceive the challenges of teaching idiomatic expressions and how they address them in the classroom. To this end, the researcher conducted face-to-face semi-structured interviews with 30 Iranian male and female teachers who teach English as compulsory courses at all grades of senior high schools in Qom, selected through convenience sampling based on their availability and willingness to participate in this inquiry. Grounded theory was used to analyze the data. The results revealed that many teachers were concerned about the inadequacy of the textbooks used in senior high schools (Vision series), as they do not emphasize the teaching of English idiomatic expressions, even though such expressions have been included in the recent University Entrance Examinations. Regarding teaching strategies for idiom comprehension, on the other hand, the teachers often provided first language (L1) equivalents for L2 idioms, guided students' attention to contextual clues, and explained the meanings of idioms. Additionally, for idiom production, they had students make stories, conversations, or sentences using the target idioms and provided them with lists of frequent idioms to memorize and use as needed. These findings shed light on the challenges teachers face and their strategies when teaching idioms at school.
