Introduction: Sleep is a multimodal construct related to the quality of life of children and adolescents. Therefore, sleep problems might affect attention, internalizing and externalizing behaviors. During the pandemic, children were pointed as a risk group for sleep problems compared to other age groups. Objective: We aimed to conduct a systematic search in the literature, in order to investigate the effects of the COVID-19 pandemic on sleep habits in children and adolescents, addressing changes on sleep duration, bedtime and wake-up time, risk and protective factors, and the particularities of children and adolescents with neurodevelopmental disorders. Methods: The search was conducted in PubMed, Scopus, and Cochrane Library databases. After the full reading evaluation a total of 133 articles, comprising 234,852 participants from 45 countries, met inclusion criteria. Results: An increase in week sleep hours and delay in sleep and wake-up time were observed as well as a worse quality of sleep. Among the emerging risk factors were evaluated confinement, age, gender, previous diagnosis, screen use, and physical activities. For children with neurodevelopmental disorders, heterogeneity in methodology and sampling constraints do not allow generalizations. Conclusion: The most important problem in children and adolescents about sleep during the pandemic was not the number of hours, but the increase in disorders related to sleep and to changes in sleep rhythm. The understanding of sleep changes might shed light on long-term effects and consequences related to the pandemic and the relationship with stress and disorders, which deserves attention to rethink the youths' routines.