To compare dental arch form between the cases with thumb sucking, tongue thrusting and normal arch form using Euclidean distance matrix analysis__ampersandsignrdquo; Materials and Method: The sample consist of 30 patients ranging in age from 13 to 17 years were divided into three groups - Group 1- Subjects with thumb sucking habit, Group 2- Subjects with tongue thrusting habit and Group 3- Subjects without any history of habit. Study model impression was made and analysis of recorded data was carried out using a WinEDMA to compare the arch shape, size, inter-canine and inter-molar width. The statistical significance of the form difference was tested by using a __ampersandsignldquo;bootstrap__ampersandsignrdquo; procedure. Result: There was a significant arch-shape difference in the maxillary arches between thumb sucking subjects and subjects with no habits. Whereas significant arch-shape differences were found in the mandibular arch of tongue thrusting individual and those with no any habits. On comparing thumb sucking and tongue thrusting subjects, there was a significant arch-shape difference in the maxillary and mandibular arches. The arch size of tongue thrusting subjects was larger as compared to thumb sucking subjects. Conclusion: Expansion of narrow maxillary arch width in anterior region should be considered to harmonize with normal mandibular arch form in thumb-sucking subjects, whereas expansion of maxillary arch width I posterior region should be considered to harmonize with wider mandibular arch form in tongue thrusting subjects.