Background: Some research shows a link between sleep behaviours and school achievement in English-speaking children and adolescents. Aims: The current study aimed to examine the relationship between children's sleep behaviours and aspects of their school achievement in Mandarin-speaking children who are living in Taiwan. Sample: The present study reports on 69 second-grade children (age range = 6.84-8.4 years) recruited in Taipei City, Taiwan. Methods: Children's sleep behaviours were assessed through two standardized parent self-report questionnaires: the Children's Sleep Habits Questionnaire (CSHQ) and the Sleep Disturbance Scale for Children (SDSC). Children undertook three standardized tests of word reading, reading comprehension and math. Results: Key findings include: (i) sleep disturbances are more prevalent when using the CSHQ scale than the SDSC scale, (ii) around half of second graders struggle with general sleep disturbances as observed by the CSHQ scale, (iii) children who go to bed before 22:00 and have at least 9-h sleep tend to exhibit fewer sleep disturbances, (iv) parasomnias as measured by the CSHQ are negatively correlated with reading comprehension after controlling age and nonverbal IQ, and (v) the amount of sleep (naps) during daytime is negatively correlated with Chinese character recognition, reading comprehension and math after controlling age and nonverbal IQ. Conclusions: There is growing awareness of the value of research that spans culturally and linguistically diverse populations. Our study contributes to ongoing discussions about the relationship between sleep, and skills in reading and math in school-aged children in Taiwan.