Abstract Background: Recommended levels of youth physical activity (PA) should emerge from data related to important health outcomes. The purpose of the present study was to establish criterion-referenced standards for PA (using pedometer-assessed steps/day) related to healthy body composition. Methods: This is a secondary analysis of an existing data set (including pedometer-assessed PA and objectively measured BMI) of 1,954 children (995 girls, 959 boys; ages 6–12 years) from the USA, Australia, and Sweden. The contrasting groups method [M.J. Sarif, Introduction to Measurement in Physical Education and Exercise Science, St. Louis, MO: Mosby College Publishing; 1986] for establishing criterion-referenced cut points was used to identify optimal age- and sex-specific standards for steps/day related to international BMI cut points for normal weight and overweight/obesity. Results: The selected cut points for steps/day for 6–12 year olds were 12,000 steps/day for girls and 15,000 steps/day for boys. Conclusions: The analytical process undertaken in this study illuminated the difference in previously used norm-referenced standards vs. criterion-referenced standards based on BMI categories. The steps/day cut points established herein, using an international sample, are higher than previously suggested normative standards but are not inconsistent with recent advances in our understanding of PA needs in youth. This analysis provides the foundation for cross-validation and evaluation of these BMI-referenced steps/day cut points in independent samples and with longitudinal study designs.