The objective of this systematic review was to comprehensively study the criterion-related validity of the existing field-based fitness tests used in children and adolescents. The studies were scored according to the number of subjects, description of the study population and statistical analysis. Each study was classified as high, low and very low quality. Three levels of evidence were constructed: Strong evidence, when consistent findings were observed in ≥3 high-quality studies; moderate evidence, when consistent findings were observed in 2 high-quality studies; and limited evidence when consistency of findings and/or the number of studies did not achieve the criteria for moderate. The results of 73 studies (50 of high-quality) addressing the criterion-related validity of field-based fitness tests in children and adolescents indicate that: There is strong evidence indicating that the 20m shuttle run test is a valid test to estimate cardiorespiratory fitness; handgrip strength test is a valid measure of musculoskeletal fitness; skinfold thickness and body mass index are good estimates of body composition, and waist circumference is a valid measure to estimate central body fat. We found moderate evidence that the 1-mile run/walk test is a valid test to estimate cardiorespiratory fitness. A large number of other field-based fitness tests presented limited evidence, mainly due to a limited number of studies (1 for each test). The results of the present systematic review should be interpreted with caution due to the substantial lack of consistency in reporting and designing the existing validity studies.