The Ireland national rugby union team is the men's representative national team for the island of Ireland in rugby union. The team represents both the Republic of Ireland and Northern Ireland. Ireland competes in the annual Six Nations Championship and in the Rugby World Cup. Ireland is one of the four unions that make up the British & Irish Lions – players eligible to play for Ireland are also eligible for the Lions.

Rugby union football, commonly known simply as rugby union or more often just rugby, is a close-contact team sport that originated at Rugby School in England in the first half of the 19th century. Rugby is simply based on running with the ball in hand. In its most common form, a game is played between two teams of 15 players each, using an oval-shaped ball on a rectangular field called a pitch. The field has H-shaped goalposts at both ends.