In the course of less than 100 years, children's sport in the Scandinavian countries has been going through a remarkable transition. By the turn of the twentieth century, voluntary sport participation was primarily an adult domain, and children's opportunities for participation were generally limited to a small selection of sports and primarily through the public school system. Today, children's sport is an important public health and welfare issue in all of the Scandinavian countries, and children are far more sport active than adults, and the majority of children's sports participation takes place in voluntary sport clubs or in commercial sport settings. The comparative analyses show that the states of Denmark, Norway and Sweden have willingly and frequently sought to regulate school sport. By contrast, traditions regarding the voluntary sport organizations have been much more diverse and ranged from heavy interference in Norway to almost no interference in Denmark.