In the contemporary orthodontics, the number of people who demand orthodontic treatment to improve their psychosocial issues related to facial esthetic is constantly increasing. Even in treatment plans, appearance and esthetic gain more attention.The purpose of this study was to determine the need for orthodontic treatment on the basis of the dental aesthetic index (DAI) in the Iranian students of Ahvaz city.This cross sectional study was performed on 900 students aged between 11 - 14 years (450 boys, 450 girls). Schools were selected based on random cluster sampling from different parts of the city. Students\ who had or were having orthodontic treatment including those on interceptive orthodontics, were excluded from the study. Two questionnaires were used; the first one included different DAI criteria, and the second one included two questions about orthodontic treatment need and satisfaction of personal dental appearance. The results were analyzed by Chi-Square and T test.In 70.9% of the students, DAI score was 13 - 25, 19.2% of the samples had a DAI score of 26 - 30, the DAI score of 7.8% was 31 - 35, and in 2.1% the DAI score was greater than 35. The association between the DAI score and sex was not statistically significant (P = 0.778). In relation to orthodontic treatment need, 44.8% of students answered positively, while in 55.2% the answer was negative. In relation to satisfaction with appearance, 21% of the students were satisfied with their appearance, 59% were relatively satisfied, and 19.9% were not satisfied with their appearance. The association between DAI score and the need for orthodontic treatment and satisfaction of dental appearance was significant (P = 0.000).In comparison to other studies, the students in Iran (Ahvaz) have a better dental appearance and less need for orthodontic treatment. Significantly positive correlations were found between the DAI and satisfaction of dental appearance, orthodontic treatment need and student's perception.