This study ascertained the influence of orthodontic appliances on subjective ratings for social competence (SC), intellectual ability (IA), psychological adjustment (PA), and attractiveness in young adult orthodontic patients. A cross-sectional analytical questionnaire study was conducted with 130 undergraduates from the UK. Each participant was asked to look at a single, randomly assigned colour photograph of a young adult female and then asked to make judgements concerning her personal characteristics. Five modified photographs of the same young adult female were used: (1) no appliance, (2) stainless steel fixed orthodontic appliance, (3) ceramic fixed orthodontic appliance, (4) gold fixed orthodontic appliance, and (5) clear colourless aligner. Likert scales with higher scores indicating more positive ratings were used. The results were analysed using chi-square test, one-way univariate analysis of variance, and post hoc Tukey-B and Kruskal-Wallis tests. The results showed that greater perceived IA was associated with the appearance of no appliance (mean values: 7.56) rather than steel (6.67) or ceramic appliances (6.65) but similar to the gold (7.35) and aligner (7.08) appliances. No significant differences between the different orthodontic appliance appearances were found for SC and PA. A trend existed where the no appliance image (resembling a lingual appliance) or clear aligner was considered more attractive than the visible buccal fixed appliances. In the absence of other information, the judgements an individual young adult makes concerning the personal characteristics of a young adult are influenced by dental appearance and orthodontic appliance design. This may influence orthodontic appliance choice.