The study was conducted on 80 students studying at School of Odonto - Stomatology and aimed to description of skeletal difference between the maxillary width and the mandibular width. the authors used a cross - sectional study to investigate the width different between the maxillary and mandibular of dental students. In the frontal cephalometric, the maxillary width is the distance between two Mx points, the width of the mandible is distance between two Ag points. Results showed that average maxillary width was 68.33 +/- 2.64 mm in male, 64.89 +/- 3.31 mm in female. The average mandibular width was 85.85 +/- 2.32 mm in male, 84.28 +/- 4.31 mm in female, maxillomandibular transverse difference index is accounted for 17.67 +/- 3,43 mm. In conclusion, the average maxillary and mandibular male widths were significantly larger than female widths. However, the Vietnamese skeletal difference between the maxillary width and the mandibular width is smaller than the average value of Rickett.