The purpose of this study was to evaluate the accuracy of airway measurements from lateral cephalograms, cone-beam computed tomographic (CBCT) lateral reconstructions, and CBCT axial planes, as well as to correlate these findings with area measurements acquired with the latter imaging method. Landmarks were defined for the measurements of naso- and oropharynx of 30 patients (12 males and 18 females, mean age 17.5 years), for different planes, using linear antero-posterior measurements and the corresponding area. Analysis of variance showed significant differences in the linear measurements of the oropharynx between the two methods, although all measurements assessed corresponded to the respective areas. The linear measurements of the airway space obtained using the different techniques correlated positively with the respective area measurements, which demonstrate the reliability of the investigated techniques.