The present study investigates 110 EFL teachers’ perception of the gravity of ten types of grammatical errors made by EFL learners in terms of acceptability. Moreover, it examines the relationship of age, gender, academic degree, years of teaching experience, and the highest level taught with the teachers’ judgements. Results revealed that the teachers’ evaluations form a hierarchy in which errors are placed at different gravity levels in accordance with their level of acceptability. Moreover, the three variables of academic degree, years of teaching experience, and the highest level taught had a positive correlation with the teachers’ evaluations. This study suggests that teachers should make their evaluations systematic, treat errors in accordance with their priority, and become aware of the factors that contribute to evaluations of grammatical errors.