In Harry Potter and the Goblet of Fire, the competition selecting champions from three wizarding schools is the Triwizard Tournament.
The tournament is an international magical contest involving Hogwarts School of Witchcraft and Wizardry, Beauxbatons Academy of Magic, and Durmstrang Institute. Traditionally, one champion represents each school, and the contestants complete three dangerous tasks.
Harry becomes an unexpected fourth champion after the Goblet of Fire selects his name, despite him being below the tournament’s stated age. This unusual selection drives much of the novel’s plot and eventually forms part of a plan involving Lord Voldemort.
The tournament should not be confused with the Quidditch World Cup, which Harry attends near the beginning of the novel. The Triwizard Tournament is also distinct from Hogwarts’s internal House Cup competition, which awards points to students in the four Hogwarts houses.