Background and Purpose: Oral health is the key factor for ceaseless orthodontic treatment. This study aimed to investigate the knowledge, attitude, and practice of patients with fixed orthodontic appliances about oral health care.
Materials and Methods: In this descriptive-analytical cross-sectional study, 201 patients referred to the Orthodontics Department of Yazd Dental Faculty, Yazd City, Iran, were recruited by convenience sampling between August 2021 and March 2022. A valid and reliable questionnaire was used, containing demographic information and 7 knowledge questions, 7 attitudinal, and 8 practical questions regarding oral health. The data were analyzed with the t-test and analysis of variance in SPSS software, version 25.
Results: The Mean±SD age of participants was 19.65±6.03 years within an age range of 10-37 years. The participants had moderate knowledge and poor practice of oral health. No significant correlation was seen between patients’ knowledge and practice scores (P>0.05). Demographic variables had no significant effect on the attitudinal questions. 
Conclusion: Oral health knowledge among patients undergoing fixed orthodontic treatment was evaluated as “moderate” and their practice as “poor.” There are some negative attitudes about orthodontic treatment among patients, such as being an unsafe treatment in pregnancy or being impossible in adulthood, that should be rectified. Educational interventions are suggested as the patients’ knowledge, attitude, and practice of oral hygiene during orthodontic treatment should be improved.