The aim of this study was to investigate the role of teeth sizes and its relationship with the development of buccal ectopia for maxillary canines،that could contribute to the aetiology of canines ectopia ,between males and females in the sample of Syrian society. The study models have been obtained, the mesiodistal width was measured for all upper and lower teeth except of second and third molars by using electronic caliper, data collected then analyzed and got results.