Obstructive sleep apnea (OSA), which occurs in 1-4% of children, is a serious condition where a person stops breathing periodically during sleep because their airway closes. Untreated, it is associated with high blood pressure, behavioural problems, and lower quality of life. While early diagnosis and treatment are critical, there are significant barriers to access to a sleep study (the best diagnostic test). Questionnaires and overnight oxygen level recordings are limited in their ability to identify OSA. Better screening tools are needed to identify and prioritize children for sleep study testing. Short video clips, recorded using smartphones by parents, may be a useful tool to identify children at risk of OSA who would most benefit from a sleep study. The study aims to evaluate the ability of home smartphone video clips as a screening tool for moderate-severe OSA in children referred for a sleep study. The utility of video clips will also be compared to questionnaires and overnight oxygen saturation recordings. The investigators believe that the video clips will be able to predict moderate-severe OSA in children and that they will be better than standard clinical questionnaires or oxygen recordings. This multi-centre study will include 625 children referred for sleep studies for suspected OSA. Parents will be asked to record short video clips of their child sleeping, which will be rated for the presence and severity of OSA. Children will then undergo a sleep study, and parents will complete a questionnaire about sleep symptoms. Oxygen level recordings will be extracted from the sleep study. The diagnostic accuracy of video clips will be determined and compared to the questionnaire and oxygen level recording. This new approach to screening for pediatric OSA using widely available technology will allow children at the highest risk for moderate-severe OSA to be diagnosed and treated earlier, minimizing the risk of long-term complications.