The history of the Ireland national rugby union team began in 1875, when Ireland played its first international match, a 0–7 loss against England. Ireland has competed in the Six Nations (formerly known as the Five Nations, and originally known as the Home Nations) rugby tournament since 1883. The Ireland national rugby union team has also competed at the Rugby World Cup every four years since its inception in 1987.

Dublin University was the first organised rugby football club in Ireland, having been founded in 1854. The club was organised by students who had learnt the game while at English public schools. During the third quarter of the nineteenth century, and following the adoption of a set of official rules in 1868, rugby football began to spread quickly throughout Ireland, resulting in the formation of several other clubs which are still in existence, including NIFC (1868); Wanderers (1869); Queen's University (1869); Lansdowne (1873); Dungannon (1873); Co. Carlow (1873); UCC (1874); and Ballinasloe (1875) which amalgamated with Athlone to form Buccaneers.

In 1874, the Irish Football Union (reconstituted as the Irish Rugby Football Union after unification with the North of Ireland Union) was formed. Ireland lost their first test match against England 7–0 at the Oval on 15 February 1875. Both teams fielded 20 players in this match, as was customary in the early years of rugby union;