The aim of this project was to study the impact from Turner syndrome (TS) karyotype and age on dental arch morphology and palatal height and to compare the variables in TS with reference data from non-TS females with normal occlusion. Plaster casts from 76 females with TS (6-50 years) were analysed with respect to dentoalveolar arch dimensions and palatal height. The TS females were divided into the karyotype categories: i) 45,X ii) 45,X/46,XX iii) isochromosome, and iv) other. The 45,X/46,XX karyotype exhibited fewer statistically significant variables differing from the reference group compared with other karyotypes. TS females showed increased dentoalveolar depths, decreased maxillary but increased mandibular width, decreased posterior segments, and decreased mandibular circumference compared with the reference group. In opposition to previous reports, the palatal height did not differ compared with non-TS females. Age had an impact on nine of the variables. We conclude that the present dental arch deviations are reflecting the high frequency of malocclusions reported in TS and the subsequent need for orthodontic treatment, which might possibly be lower in the 45,X/46,XX karyotype. The palatal height did not differ from the reference group, but instead the narrow maxilla might contribute to an illusion of a higher palate. We therefore suggest using the nomination 'narrow palatal vault' instead of the commonly used term 'high palatal vault'.