This study examined the effects of rapid palatal expansion (RPE) and maxillary protraction headgear therapy in 18 patients with a skeletal Class III malocclusion (11 girls and seven boys; mean age 10.9 years) on upper airway dimensions compared with an untreated control group (nine girls and eight boys; mean age 10.9 years). Pre- and post-treatment cephalometric radiographs were traced and analysed at similar time intervals. The average treatment time was 6.94 +/- 0.56 months. Wilcoxon's test was used for intragroup comparisons and the Mann-Whitney U-test for intergroup comparisons. A significant increase occurred in the maxillary forward position. Mandibular forward movement and downward and backward rotation were inhibited. In addition, the upper incisors were proclined (P < 0.001), and the lower incisors were significantly retroclined (P < 0.05). When the treatment and control groups were compared, the upper airway linear measurements (pns-ad1, pns-ad2, APW-PPW, APW'-PPW') and the nasopharyngeal area had increased in the treatment group. These results demonstrated that maxillary expansion together with protraction of the maxilla improved naso- and oropharyngeal airway dimensions in the short term.