Purpose: Teachers, like other human beings are affected by the fallacy of ‘Halo Effect’. Regarding their role in teaching and training students, this study tried to investigate the halo effect in relation to appearance, gender, and proficiency of teachers. Methodology: In order to perform such an evaluation, this study used 350 males and female EFL students and 53 males and female EFL teachers of universities and institutes of Karaj. Three questionnaires (appearance, gender, and proficiency questionnaires) were designed and evaluated. The questionnaires were distributed among students and after the students answered them the questionnaires were gathered. Findings: The results of this study showed that proficiency was the most important feature for both male and female students. The second important feature for students was teacher's appearance. Gender was the least important feature of a teacher for students. The students think of the proficiency as the most important factor. According to the results of data analysis of students' final marks in real situation (classroom environment), the most important factor affecting the achievement of students in a positive way was appearance of a teacher. Thus, appearance of a teacher can cause halo effect. Teachers and educational system can benefit from the results of this study. Conclusion: Teachers should be sensitive to proficiency and appearance in order to be better teachers, and educational system can understand strengths and weaknesses of the process of hiring teachers regarding appearance and proficiency.
