Lacrosse is a contact team sport played with a lacrosse stick and a lacrosse ball. It is the oldest organized sport in North America, with its origins with the indigenous people of North America as early as the 12th century. The game was extensively modified by European colonists, reducing the violence, to create its current collegiate and professional form.

Players use the head of the lacrosse stick to carry, pass, catch, and shoot the ball into the goal. The sport has five versions that have different sticks, fields, rules and equipment: field lacrosse, women's lacrosse, box lacrosse, lacrosse sixes and intercrosse. The men's games, field lacrosse (outdoor) and box lacrosse (indoor), are contact sports and all players wear protective gear: helmet, gloves, shoulder pads, and elbow pads. The women's game is played outdoors and does not allow body contact but does allow stick to stick contact. The only protective gear required for women players is eyegear, while goalies wear helmets and protective pads. Lacrosse sixes is played by both men and women on a smaller field, and is the most common version at multi-sport events. Intercrosse is a mixed-gender non-contact sport that uses an all-plastic stick and a softer ball.

The modern sport is governed by World Lacrosse and is the only international sport organization to recognize First Nations bands and Native American tribes as sovereign nations. The organization hosts the World Lacrosse Championship for men, the Women's Lacrosse World Cup, the World Indoor Lacrosse Championship for box lacrosse, and the Under-19 World Lacrosse Championships for both men and women. Each is held every four years. Lacrosse at the Summer Olympics has been contested at two editions of the Summer Olympic Games, 1904 and 1908. It will be contested at the 2028 Olympic Games in the lacrosse sixes format. It was also held as a demonstration event at the 1928, 1932, and 1948 Summer Olympics.