Background: Tooth size specifically the mesiodistal dimension has an important role in normal occlusion and in arch space analysis as it affects treatment planning and the final results in orthodontic treatment. Tooth size differs among and within populations.

Objectives: The aim of the current study was to measure the mesiodistal widths of the mandibular incisors, maxillary and mandibular canines and premolars in a group of Egyptian children in Suez Governorate and to correlate between the widths of these teeth to formulate normative data for the Egyptian children.

Materials and Methods: 12-15 year old children (150 boys and 150 girls) from Suez Governorate were included in the present study. The measurements of the mesiodistal widths of the teeth were conducted on dental casts by a digital caliper

Results: The means of the mesiodistal widths of the boys' teeth were significantly larger than those of the girls. Also, there was no statistically significant difference between the right and left sides in girls. However, in males the right mandibular second premolar was significantly bigger than the left side.

Conclusion: Sexual dimorphism is present between boys and girls where boys had larger teeth than girls. There were no statistically significant differences between the right and left sides in girls. But in boys only the mandibular second premolar showed slight statistically significant difference. The mandibular permanent incisors can be used in the prediction of the mesiodistal widths of the maxillary and mandibular permanent canines and premolars due to positive correlation between them.