Objectives: To determine patient and parent/guardian motivation, expectation and understanding of orthodontic treatment. Design: A self-completion questionnaire survey of new patients referred for orthodontic assessment. Setting: Specialist practices in Surrey and Berkshire (United Kingdom). Participants: A total of 500 questionnaires were issued (250 were issued to patients and 250 to parents). Methods: The survey was based on a self-completed questionnaire which was issued at the assessment appointment. Both questionnaires were adapted and extended from originally validated questionnaires previously used in a hospital setting. Patients and parents were asked to complete separate anonymous questionnaires. The patient questionnaire consisted of 24 closed-ended questions divided into three domains: motivation; understanding; and expectation of orthodontic treatment. The parent questionnaire consisted of 13 questions covering the same three domains Results: The response rate for the patient and parent questionnaires was 95% and 91%, respectively. Forty-seven percent of the patients were aged 11-13 years. In 77% of cases, the referral was initiated by their dentist. Only 3% of patients thought there was nothing wrong with their teeth. There was a poor understanding of what a retainer is and for how long patients are expected to use it. Conclusions: Referral for orthodontic treatment was initiated by the patients' general dental practitioner in the majority of the cases. The anticipation of improved dental appearance was a prime motivating factor. Participants had realistic expectations and there was a good acceptance of appliances and dental extractions for orthodontic treatment. Nevertheless, both patients and parents/guardians were less well informed on the nature and duration of orthodontic retention. Keywords motivation, expectations, orthodontic treatment, patients, parents, quality of life and orthodontics, health services and quality of life aspects, psychological aspects of orthodontics Date