This study explores university lecturers’ perceptions and evaluations of the use of idioms in English academic writing. Adopting a qualitative research design, data were collected through semi-structured interviews with 12 English lecturers, each of whom had at least three years of experience teaching academic writing courses. The findings indicate that lecturers do not regard idioms as inherently inappropriate in academic writing; rather, idioms are viewed as a conditional discourse resource that may be acceptable when they serve clear argumentative or organizational functions and conform to academic style. The participants emphasized the importance of distinguishing between academically appropriate idioms and colloquial expressions, and identified several challenges faced by EFL students, particularly stylistic mismatch and semantic misuse. The study highlights the central role of lecturers in guiding students’ awareness of idioms and in establishing academic writing norms. The findings contribute a pedagogical perspective to existing research on idioms in academic discourse.