BACKGROUND: Sleep deprivation is common among teenagers. The aim of this study was to investigate the relationship between sleep duration, wake/sleep symptoms, and academic performance among Hong Kong students. MATERIALS AND METHODS: The sleep habit questionnaires were distributed to all Year 11 students at an international school that catered to different ethnic groups in Hong Kong. Analysis of various parameters of academic performance and sleep habits and their relationships were undertaken. RESULTS: Fifty-nine students were recruited. The average sleep duration in this group was 7.23 h. The overall prevalence of excessive daytime sleepiness (defined as an Epworth Sleepiness Scale score of >10) was 25.4%. Eleven subjects had excessive class sleepiness, defined as high likelihood to fall asleep during at least one school session. Mathematics performance was positively correlated with sleep duration. Excessive sleepiness on rising was identified as a significant risk factor for poor performance in English and Mathematics. Sleepiness during the third and fourth lessons was identified as a significant risk factor for poor performance in Mathematics only. CONCLUSION: Sleep deprivation was common in the studied cohort and it was associated with a decrease in Mathematics performance. Excessive sleepiness on rising and sleepiness during third and fourth lessons were associated with poorer grades in Mathematics and English. Excessive daytime sleepiness was reported in 25% of students. Bruxism and snoring were associated with excessive daytime sleepiness.