Sleep disorders are very common among teenagers. One of possible reasons is a discrepancy between social and biological activity of children. It is known that adolescents with a late chronotype (e.g., a later midpoint of sleep) have a lowered academic achievement. The aim of our study was to evaluate sleep quality and other sleep-wake characteristics in relation to academic scores self-reported by teenagers living in urban and rural areas of Republic of Karelia.Five hundred respondents, aged 10-17 years, participated in a questionnaire survey of chronotype and sleep quality. The Munich chronotype questionnaire (MCTQ) and the Pittsburgh Sleep Quality Index (PSQI) were used. Sleep duration during week and weekend, sleep quality and hygiene were assessed.A decrease in sleep duration in adolescents, aged 10-18 years, was observed. A larger social jetlag was significantly higher in girls compared to boys. Gender had a significant impact on sleep quality. More than 10% of the total variation in academic achievement of Karelian teenagers can be explained by the difference in their gender and average sleep duration.