Background: Discrepancies between tooth sizes can cause orthodontic problems such as crowding and improper occlusion. By identifying these problems, better orthodontic treatment outcome can be achieved. The aim of this study is to identify anterior tooth size discrepancies among 4 different types of malocclusion i.e. Class I; Class II division 1 (II/1); Class II division 2 (II/2); and Class III. Methods: A retrospective study was carried out using 200 orthodontic study models where 50 study models were taken for each of the 4 malocclusion groups. The samples were selected using random sampling technique based on the orthodontic waiting list in the Orthodontic Department, Dental Faculty, UKM. All anterior teeth were measured by the same examiner at the largest mesio-distal dimension, using a digital caliper recorded up to 0.01 mm. Comparison between the 4 groups of malocclusion were made intra-arch using individual tooth size measurement and inter-arch using Anterior Bolton Index (ABI). Results: For the intra-arch assessment, Class II/1 had significantly the largest upper and lower anterior tooth size except for its upper canine and lower central incisor. Class III group had insignificantly the smallest mandibular anterior teeth compared to other malocclusion groups. For inter-arch assessment, Anterior Bolton Index (ABI) of all samples was 79.2 ± 3.94%. The highest ABI was noted in Class II / 2 of 80.3 ± 4.71%. However, no significant differences were found among the 4 malocclusion groups (p>0.05). Conclusion: Most of the anterior teeth in Class II division 1 were the largest of all. No significant difference in the inter-arch tooth size discrepancies were detected among all malocclusion groups.