Introduction YouTube is a popular social media platform that is being increasingly used for the distribution of healthcare-related information. To date, there appear to be no published studies assessing the quality of oral hygiene instruction provided by YouTube videos.Objective To assess the availability, quality and accuracy of patient-focused YouTube videos aiming to provide oral hygiene instruction.Method YouTube videos meeting the inclusion criteria were evaluated for quality and information accuracy using an eight-item, evidence-based checklist relating to important aspects in the prevention of caries and periodontal disease.Results Fifty-two relevant videos were included; 20 videos (38.5%) were produced by lay people (social media influencers and bloggers) who had no professional qualifications. None of the included videos contained accurate information relating to all eight items of the evidence-based checklist. Seven videos contained none of the information from the checklist. Numerous videos contained health advice which was not scientifically sound.Conclusion The results of this study highlight that currently available YouTube videos may not contain evidence-based information relating to oral hygiene instruction. There are also concerns regarding the lack of regulation and quality assurance processes in the development of healthcare-related YouTube videos. Currently, clinicians should be cautious when advising patients to utilise YouTube as a source of information regarding oral health.