The diagnostic and treatment planning of orthodontics heavily depends on the function of breathing. Numerous studies have documented significant correlations between dentofacial, craniofacial, and pharyngeal anatomy. The link between mouth breathing and a narrowed airway that results in obstructive sleep apnea has been highlighted by numerous writers. Correcting either oral or bone issues, or both can eliminate related symptoms. It would be highly interesting to understand how the airway changes in size during orthodontic treatment by utilizing different treatment methods to comprehend and interpret the airway during diagnosis and treatment planning. Therefore a complete understanding of the concept of airway should be considered important. This chapter gives us an insight into the intricate detailing of how the various orthodontic and dentofacial orthopedic treatment signifies the changes in the dimensions of the pharyngeal airway.