The executions during the Irish Civil War took place during the guerrilla phase of the Irish Civil War (June 1922 May 1923). This phase of the war was bitter, and both sides, the government forces of the Irish Free State and the anti-Treaty Irish Republican Army (IRA) insurgents, used executions and terror in what developed into a cycle of atrocities. From November 1922, the Free State government embarked on a policy of executing Republican prisoners in order to bring the war to an end. Many of those killed had previously been allies, and in some cases close friends (during the Irish War of Independence 19191921), of those who ordered their deaths in the civil war. In addition, government troops summarily executed prisoners in the field on several occasions. The executions of prisoners left a lasting legacy of bitterness in Irish politics.

The use of execution by the Irish Free State in the Civil War was relatively harsh compared to the recent British record. In contrast with 81 official executions by the Irish Free State government, the British had executed 24 IRA volunteers during the 191921 conflict.

The Irish Republican Army (IRA) is a name used by various paramilitary organisations in Ireland throughout the 20th and the 21st centuries. Organisations going by this name have been dedicated to irredentism through Irish republicanism, the belief that all of Ireland should be an independent republic free from British rule.The original Irish Republican Army (1919–1922), often now referred to as the "old IRA", was raised in 1917 from members of the Irish Volunteers and the Irish Citizen Army, later reinforced by Irishmen, formerly in the British Army in World War I, who returned to Ireland to fight against Britain in the Irish War of Independence. In Irish law, this IRA was the army of the revolutionary Irish Republic as declared by its parliament, Dáil Éireann, in 1919.

In the century that followed, the original IRA was reorganised, changed and split on multiple occasions, to such a degree that many subsequent paramilitary organisations have been known by that title – most notably the Provisional Irish Republican Army which was a key participant during the Troubles. The contemporary IRA organisations each claim the sole right to use that name, as they each insist they are the only legitimate descendants of the original IRA.