Introduction: The largest sinus is the maxillary sinus. The growth and development commence during fetal development (3rd Month) by the infundibulum present on ethmoid bone. Post birth, it expands in the lateral direction during the growth spurt period (Birth - 3 years and 7 - 12 years). Aim/Objectives: The aim was to determine the relation of mandibular body length with the area dimensions of the maxillary and frontal sinus using digital lateral cephalogram. Materials and Methods: 60 Digital lateral cephalograms were equally divided to form 3 groups of Class I, Class II, Class III patients comprising 20 each with equal inclusion of male and female patients. The Dolphin 2017 software was used to calculate the area dimensions and individual variables of both the paranasal sinuses, mandible size and both cranial bases with their growth pattern. Results: Class III malocclusion showed greater dimensions and surface area compared to those in other groups. Mandibular body length showcased a positive correlation to the sinus dimensions. Results obtained showed that the mean value of frontal sinus area for Class I was 335.59 mm2, Class II was 257.64 mm2 and Class III was 393.82 mm2. The mean value of maxillary sinus area for Class I was 973.70 mm2, Class II was 690.48 mm2 and Class III was 1078.75 mm2. Males showed greater values than the female group. Conclusion: Class III malocclusion showed higher values for dimensions and surface area compared to the other sample groups. Values calculated had a positive relation with both the cranial bases and mandibular body size.