Background: Sleep problems may have different influences on students' academic performance. We investigated the prevalence of sleep patterns, naps, and sleep disorders, and their associations with academic performance in Hong Kong adolescents. Methods: In 2007-2008, 22,678 students aged 12-18 (41.6% boys) completed a questionnaire on sociodemographic characteristics, sleep patterns and problems, and lifestyle factors including exercise, smoking, alcohol drinking, and academic performance. Results: The prevalence of having greater than 8 hours of sleep was higher on holiday nights (86.4%) than on school-day nights (27.4%). Sleeping after midnight was more common before holidays (49.3%) than before school days (19.9%). Symptoms of insomnia and obstructive sleep apnea (OSA) were reported by 21.5% and 34.4% of students. Having greater than 2 hours of weekend sleep delay was associated with poor academic performance with an odds ratio (OR) (95% confidence interval) of 1.46 (1.29-1.65). However, having 1-2 hours and greater than 2 hours of weekend wake-up delay were both associated with less likelihood of poor academic performance with ORs of 0.64 (0.56-0.73) and 0.69 (0.59-0.80). Other factors associated with poor academic performance included greater than 2 hours of sleep debt, OR of 1.17 (1.03-1.33); having any insomnia symptoms in the past 30 days, OR of 1.27 (1.17-1.37); and having any OSA symptoms at least weekly, OR of 1.23 (1.14-1.32). Napping in the past 5 school days was only marginally associated with poor school performance with an OR of 1.08 (1.00-1.16). Conclusion: Poorer academic performance was associated with sleep debt, and symptoms of insomnia and OSA. Sleep compensation but not naps may be a protective factor of poor academic performance. (Contains 4 tables.)