['To examine the prevalence and correlates of habitual snoring in senior high school students in Korea.', 'A cross-sectional survey.', 'Ten high schools in the southern part of Seoul, Korea.', 'A total of 3,871 high school students (2,703 male students and 1,168 female students; age range, 15 to 18 years; mean age: male students, 16.8 years; female students, 16.9 years) who were attending the 11th grade.', 'Data were collected on sociodemographic characteristics, school performance, and patterns of sleep and sleep-related disturbances. The overall prevalence of habitual snoring was 11.2% (boys, 12.4%; girls, 8.5%). The mean total sleep time was similar in habitual snorers vs nonsnorers (6.4 and 6.3 h per day, respectively). Frequency of snoring increased significantly with body mass index (BMI) [p < 0.001], cigarette smoking (p < 0.01), prevalence of witnessed apnea (p < 0.001), and Epworth sleepiness scale score (p < 0.001). The frequency of snoring increased with a decline in school performance (p < 0.001). For those whose school performance was low, there was a 35% excess in the odds of habitual snoring vs those whose school performance was high (odds ratio, 1.35; 95% confidence interval, 1.01 to 1.78).'] Does prevalence and correlate of habitual snoring in high school students?