The aim of this research was to investigate natural head posture, nasopharyngeal airway and cranial base relations in different head types. The material consisted of lateral cephalograms obtained from 99 adult individuals whose age range was between 19 and 29 (Mean 2 1.8 years ± StD 2.2 years). Head length and width measurements were clone and grouped as Hyperbrachycephal. Brachycephal. Mesocephal and Dolichocephal according to cephalic index. Difference of posture, airway and cranial measurements between head types was investigated by variance analysis in the total group which consisted of 99 individuals, the relations between posture and airway measurements in head type sub-groups was investigated by correlation analysis. Besides, the correlations between cranial base and posture measurements were evaluated in each head type group. Findings indicated that airway and posture were not correlated in the total group while significant negative correlations were observed in Dolichocephal grup. Cranial base dimensions were found correlated with posture. S-Ba/N-Ba ratio showed important correlations with posture (P<0.05) in Hyperbrachy and Dolichocephal groups, however, this ratio was not distinct between head types. It has been suggested that, cranial base dimensions were effective on posture because of center of gravity of the head and sagittal nasopharyngeal airway parameters showed important negative correlations in Dolichocephal group which has the highest head length range among head types lead us to consider the anatomical relationship between head length and nasopharyngeal airway. Therefore, it can be stated that cranial base dimensions and morphology in which minor changes occur during development, is an important factor on head posture rather than anatomical dimensions of airway.