The Tour de Ski (TdS) is a cross-country skiing event held annually since the 2006–07 season in Central Europe, modeled on the Tour de France of cycling. The Tour de Ski is a Stage World Cup event in the FIS Cross-Country World Cup. Each Tour de Ski has consisted of six to nine stages, held during late December and early January in the Czech Republic, Germany, Italy, and Switzerland. As of 2023, the prize money for the event amount to 770,000 Swiss francs (779,000 euros), shared out on both men and women. Men's and women's events are held together on the same days, with the only difference being the distance skied.

Competitive cross-country skiing encompasses a variety of race formats and course lengths. Rules of cross-country skiing are sanctioned by the International Ski Federation and by various national organizations. International competitions include the FIS Nordic World Ski Championships, the FIS Cross-Country World Cup, and at the Winter Olympic Games. Such races occur over homologated, groomed courses designed to support classic (in-track) and freestyle events, where the skiers may employ skate skiing. It also encompasses cross-country ski marathon events, sanctioned by the Worldloppet Ski Federation, and cross-country ski orienteering events, sanctioned by the International Orienteering Federation. Related forms of competition are biathlon, where competitors race on cross-country skis and stop to shoot at targets with rifles, and paralympic cross-country skiing that allows athletes with disabilities to compete at cross-country skiing with adaptive equipment.