OBJECTIVE The aim of this study was to estimate the orthodontic treatment need in a sample of 12-year-old Yemeni school children using the dental aesthetic index (DAI). METHODS The sample comprised 3003, 12-year-old children attending school in six of the governorates of Yemen. For each subject, the standard demographic information such as gender and age was collected, after which an intraoral examination for occlusal status using the DAI was performed. RESULTS The mean (SD) of DAI score was 24.86 (8.44) points (95% CI, 24.07-25.65). Overall, 36.6% of the sample found to have a dental appearance that requires orthodontic treatment, ranging from 'selective' to 'mandatory'. Of whom, 19.0% presented with severe and handicapping malocclusion, requiring 'definite' and "mandatory' treatment according to the DAI (DAI ≥ 31). Although there was no gender difference in the mean DAI score (P > 0.05), the sex distribution of the DAI treatment categories was significantly different (Chi-square = 13.258, df = 3, P = 0.004). The results of the individual DAI components showed that about 8% of the sample had more than one missing permanent teeth. Anterior maxillary and mandibular irregularity occurred in more than 33% of the sample. More than 30% of the children examined showed signs of crowding. Spacing in the incisal segments occurred in almost 25% of the sample. Almost 30% of the sample had an antero-posterior molar relation discrepancy. CONCLUSIONS According to the findings of this study, almost one in five of the evaluated Yemeni school children had a DAI score above or equal to 31 points, suggesting highly desirable or mandatory orthodontic treatment need.