Background: Deficient sleep is linked to detrimental outcomes in health and school performance for adolescents. This study characterized sleep patterns in Chinese adolescents preparing for the College Entrance Exam (CEE) and evaluated the association between sleep patterns, self-rated academic performance, and the CEE scores. Methods: A sample of 481 Chinese adolescents in 12th grade (ages 16-19 years) completed questionnaires about sleep patterns, academic performance, academic stress, and sociodemographic factors 4-6 weeks before the CEE in June 2013. The CEE scores for each student also were obtained. Results: A total of 21% of the students had bedtimes after 12:00 am, 78.3% had sleep latency longer than 30 minutes, 14.6% had wake time earlier than 6:00 am, and the vast majority (94.4%) had sleep duration less than 8 hours. After adjusting for selected confounders such as academic stress, prolonged sleep latency was associated with poorer self-reported academic performance, and late bedtime was associated with higher CEE score. Conclusions: Our findings highlight the complex association between sleep and academic performance. Assessing and monitoring sleep patterns in adolescents during periods of high academic demand and stress may yield important recommendations for their health and safety as well as establishing optimal sleep and study habits.