The aim of this study was to evaluate the orthodontic treatment needs in a sample of 12-year-old Yemeni school children using the Dental Aesthetic Index (DAI). Subjects and 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 intra-oral examination for occlusal status using the DAI was performed. Results: The mean DAI score was 24.86 (SD = 8.44) points (95% CI, 24.07 to 25.65). On the whole, 36.6 % of the sample found to have a dental appearance that requires orthodontic treatment, ranging from 'selective' to 'mandatory'. Of whom 19.0 % prsented with severe and handicapping malocclusion, requiring 'definite' and 'mandatory' treatment. The results of the individual variables showed that about 8 % of the sample with 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. Conclusion: According to the findings of this study, almost one of each five of the evaluated Yemeni school children in the sample had a DAI score above or equal to 31 points, suggesting highly desirable or mandatory orthodontic treatment need. The inclusion of occlusal traits as part of the index provided an opportunity to assess several occlusal characteristics in 12-year-old Yemeni children, separately. Keywords: dental aesthetic index, orthodontic treatment need, Yemen