The Real Irish Republican Army, or Real IRA (RIRA), was a dissident Irish republican paramilitary group that aimed to bring about a United Ireland. It was formed in 1997 following a split in the Provisional IRA by dissident members, who rejected the IRA's ceasefire that year. Like the Provisional IRA before it, the Real IRA saw itself as the only rightful successor to the original Irish Republican Army and styled itself as simply "the Irish Republican Army" in English or Óglaigh na hÉireann in Irish. It was an illegal organisation in the Republic of Ireland and designated a proscribed terrorist organisation in the United Kingdom and the United States.

The Real IRA waged a campaign in Northern Ireland against the Police Service of Northern Ireland—formerly the Royal Ulster Constabulary—and the British Army. It was the largest and most active of the "dissident republican" paramilitary groups operating against the British security forces. It targeted the security forces in firearm attacks and bombings, and with grenades, mortars and rockets.

The Real IRA was also responsible for bombings in Northern Ireland and England with the goal of causing economic harm and disruption, the most notable being the 1998 Omagh bombing, which killed 29 people. After that bombing, the Real IRA went on ceasefire, but resumed operations in 2000. In March 2009 it claimed responsibility for an attack on Massereene Barracks which killed two British soldiers, the first to be killed in Northern Ireland since 1997. The Real IRA has also been involved in attacks on drug dealers.

In July 2012, it was reported that Republican Action Against Drugs (RAAD) and other small republican militant groups were merging with the Real IRA. This new entity was named the New IRA by the media but members continue to identify themselves as simply "the Irish Republican Army". Small pockets of the Real IRA that did not merge with the New IRA continue to have a presence in the Republic of Ireland, particularly in Cork and to a lesser extent in Dublin.

In July 1997, the Provisional IRA called a ceasefire. On 10 October 1997, a Provisional IRA General Army Convention was held in Falcarragh, County Donegal. At the convention, Provisional IRA Quartermaster General Michael McKevitt—also a member of the 12-person Provisional IRA Executive—denounced the leadership and called for an end to the group's ceasefire and to its participation in the Northern Ireland peace process. He was backed by his partner and fellow Executive member Bernadette Sands McKevitt. The two dissidents were outmanoeuvred by the leadership and were left isolated. The convention backed the pro-ceasefire line, and on 26 October McKevitt and Sands McKevitt resigned from the Executive along with other members.

In November 1997, McKevitt and other dissidents held a meeting in a farmhouse in Oldcastle, County Meath, and a new organisation, styling itself Óglaigh na hÉireann, was formed. The organisation attracted disaffected Provisional IRA members from the republican stronghold of South Armagh, as well as Dublin, Belfast, Limerick, Tipperary, County Louth, County Tyrone and County Monaghan.

The name "Real IRA" entered common usage when in early 1998 members set up a roadblock in Jonesborough, County Armagh, and told motorists "We're from the IRA. The real IRA".

The RIRA's objective is a united Ireland by forcing the end of British sovereignty over Northern Ireland through the use of physical force. The organisation rejects the Mitchell Principles and the Good Friday Agreement, comparing the latter to the 1921 Anglo-Irish Treaty which resulted in the partition of Ireland. The organisation aims to uphold an uncompromising form of Irish republicanism and opposes any political settlement that falls short of Irish unity and independence.