Flexibility is related to specific tissue properties of the body, which aim to determine the maximum range of motion of the joints without injury. This study aimed to identify and summarize the evidence on prevalence of adequate levels of flexibility in Brazilian children and adolescents (6 to 19 years old). We performed a systematic search of studies published from 2009 to 2019 in six databases (MEDLINE/PubMed; Scopus; SportDiscus; LILACS; Web of Science; SCIELO). Fourteen studies that compiled data from 11,666 participants in seven different Brazilian states were included. All studies conducted sit and reach tests to assess flexibility. Among all the children and adolescents in the analyzed studies, 58.9% of the total (62.0% of boys and 50.9% of girls) had adequate flexibility. We conclude that more than half of Brazilian children and adolescents have adequate flexibility for health.