Various predictive research designs have been used to discover the relationship between learners' aca- demic achievement and the degree of teacher-student interactions they receive individually or in a group and the mediating role of their academic interest in learning. How these relation- ships/correlations work in an English as a Foreign Language (EFL) setting, however, has remained a rarely investigated topic. This study explored the effects of teacher-student interactions on academic achievement by focusing on the mediating role of academic interest. In doing so, 218 EFL learners (102 males and 116 females) who were undergraduate English students at Islamic Azad University, Tabriz Branch were selected out of 645 students through the stratified random sampling method. This number of the learners was determined according to a sample size calculator for structural equation modeling (SEM). A correlational survey design was employed to investigate the purposes of the study through the SEM framework. The results demonstrated a significant correlation among variables and multiple predictions of students' academic achievement through the predictor variables. The outcomes confirmed that the increased interest of the EFL learners in learning and their interactions with their teachers could considerably contribute to improvement of their academic performance. پرونده مقاله