Nasal breathing protects the upper airway and is responsible for adequate craniofacial development. It is believed that long-standing obstruction causes mouth breathing, which has a negative impact on the craniofacial complex. Aim: The study aimed to verify the effects of mouth breathing on the dentofacial structure by employing cephalometric analysis. Materials and methods: The present study was conducted on 68 patients (34 mouth-breathing group or study group and 34 nasal-breathing group or control group) aged 6–14 years. Study subjects were screened based on the inclusion and exclusion criteria. Clinical assessment of nasal function was done to select the mouth breathing patients and referred for ear, nose, and throat (ENT) clearance. Lateral cephalograms were taken for the study subjects, including both nasal and mouth breathers, over which selected landmarks were marked to evaluate linear, skeletal, and dental angular variables for comparison with cephalometric variables of a normal child. Results: The mean values of facial height (N-Me, ANS-Me) and mandibular plane angle (SN-GoGn) were significantly higher for mouth breathers. The gonial angle (Ar-GoMe) for ages 6–14 years was significantly lower in the nasal breathing group. Conclusion: The study led to the conclusion that all subjects with a history of mouth breathing showed an increase in facial height, gonial angle, and mandibular plane angle. Clinical significance: Evaluating dentoskeletal changes in a patient with a mouth-breathing habit helps discern the importance of early identification and interception at an early age, thereby ensuring a functional environment adequate for physiological growth and dentofacial esthetics.