Objective: The aim of this study is to investigate the use of overnight oximetry to predict high Apnea–Hypopnea Index (AHI) in Hong Kong children with habitual snoring. Methodology: We have retrospectively analyzed the polysomnography (PSG) of 573 patients with habitual snoring with age ranged from 6 months to 18 years old. Patients with syndromal diagnosis or neuromuscular disorders were excluded from the study. The sensitivity, specificity, positive predictive value , and negative predictive value (NPV) of oximetry to predict AHI were calculated. Results: McGill score >1 had high specificity 99.07% and low sensitivity 16.81% to detect AHI >1. SpO2 nadir 5. Conclusion: The use of the McGill score together with nadir SpO2 in overnight oximetry can help in stratifying the severity of obstructive sleep Apnea and thus prioritizing PSG testing.