This study was undertaken to compare laypersons' and professionals' perception of soft tissue profiles of Class III adults, and to evaluate which cephalometric variables are likely to influence the profile assessment score (PAS). Lateral headfilms and coloured profile photographs of 18 skeletal Class III Caucasian adult patients (10 males, 8 females with a mean age of 24.5 years) prior to surgery, and nine adult Caucasian patients (four males, five females with a mean age of 27.4 years) with a dental Class I occlusion and no major skeletal discrepancy were included in the study. The headfilms were hand traced and digitized. Various cephalometric variables were calculated by computer software. Each printed profile photograph was evaluated aesthetically by 18 laypersons and 18 orthodontists using a 10-graded visual analogue scale (VAS) and a standard profile for calibration. Intra-observer reliability was tested and no significant error was found. Paired and unpaired t-tests were used to compare the scores. The association between various cephalometric variables and the PAS was tested. In general, compared with orthodontists, laypersons were less critical in their evaluation of the Class III profiles (+0.3 grade on the VAS) as well as the reference profiles (+0.7). The reference profiles were found to be more attractive than the Class III profiles by both laypersons and orthodontists (+2.3 grades). The degree of facial concavity had a negatively predictive value for the orthodontists' and laypersons' evaluations. The degree of facial concavity together with the steepness of the mandibular plane were negatively predictive factors for the PAS given by the orthodontists.