The Davis Cup is the premier international team event in men's tennis. It is run by the International Tennis Federation (ITF) and is contested annually between teams from competing countries in a knock-out format. It is described by the organisers as the "World Cup of Tennis", and the winners are referred to as the World Champion team. The competition began in 1900 as a challenge between Great Britain and the United States. By 2016, 135 nations entered teams into the competition.The most successful countries over the history of the tournament are the United States (winning 32 titles and finishing as runners-up 29 times) and Australia (winning 28 titles, including four with New Zealand as Australasia, and finishing as runners-up 19 times). The current champions are Russia, who beat Croatia to win their third title in 2021.

The women's equivalent of the Davis Cup is the Billie Jean King Cup, formerly known as the Fed Cup. Australia, Russia, the Czech Republic, and the United States are the only countries to have won both Davis Cup and Fed Cup titles in the same year.

The Davis Cup allowed only amateurs and national registered professional players (from 1968) to compete until 1973, five years after the start of the Open Era.Russia and Belarus were suspended after the 2022 Russian invasion of Ukraine.