Background: The purpose of this study was to evaluate the content and quality of YouTube videos on the topic of adult orthodontics. Methods: Four Turkish keywords were searched on YouTube: "orthodontic treatment in older ages" (ileri yaslarda ortodonti tedavisi); "orthodontic treatment in adults" (yetiskinlerde ortodonti tedavisi); "braces treatment in older ages" (ileri yaslarda video information and quality index dis teli tedavisi); and "braces treatment in adults" (yetiskinlerde dis teli tedavisi). A total of 184 videos, ranked according to their relevance, were examined; out of these, 52 videos on the topic of adult orthodontics were included in the study. The information content score (with a scoring system consisting of 6 questions), reliability score, (VIQI), interaction index, and viewing rate of the videos were evaluated. The Mann-Whitney U test, Student's t test, and Spearman correlation coefficients were used for statistical analysis. Results: Explanations provided on all videos included in the study were given by orthodontists, to inform patients. The average content score of the videos was 2.55 +/- 0.99 out of 6, and the reliability score was 3.07 +/- 0.92 out of 5. The VIQI score was found to be 16.05 +/- 2.76 out of 20. A total of 34 (65%) of the videos were scored as as having poor content, and 18 (35%) had rich content. Rich-content videos were observed to be significantly longer (P < 0.05) and have higher VIQI scores (P < 0.001). Conclusions: Although the information provided by YouTube videos about adult orthodontics was only moderately sufficient, this study found that YouTube is a reliable source of information. (C) 2021 World Federation of Orthodontists. Published by Elsevier Inc. All rights reserved.