The notion of scaling, as it applies to junior sport, suggests that variables such as equipment, playing area, and rules should ideally be matched to the capabilities of the child. This chapter provides a discussion of the importance of scaling in children’s sport and the potential links between scaling, backyard games, and drop-out from junior competitions. A summary of the results from research is included to provide the reader with an overview of the typical approaches that have been employed to investigate the effects of scaling, and to also highlight the specific benefits of scaling that have been reported in the research. The final sections focus upon the need for a principled approach towards scaling characterised by the application of a theoretical framework to underpin the implementation of scaling in research and practical contexts. Considerations for practitioners are provided to help guide the application of scaling by sporting associations.