Roderick O'Connor was an Irish republican revolutionary. He was Director of Engineering for the IRA in the Irish War of Independence. O'Connor opposed the Anglo-Irish Treaty of 1921 and was chairman of the republican military council that became the Anti-Treaty IRA in March 1922. He was the main spokesman for the republican side in the lead-up to the outbreak of the Irish Civil War in June of that year. On 30 June, O'Connor was taken prisoner at the conclusion of the attack by Free State forces on the Four Courts in Dublin. On 8 December 1922, he was executed along with three other senior members of the IRA Four Courts garrison. All four men were executed without trial or courts martial.

The Irish Republican Army was an Irish republican revolutionary paramilitary organisation. The ancestor of many groups also known as the Irish Republican Army, and distinguished from them as the "Old IRA", it was descended from the Irish Volunteers, an organisation established on 25 November 1913 that staged the Easter Rising in April 1916. In 1919, the Irish Republic that had been proclaimed during the Easter Rising was formally established by an elected assembly, and the Irish Volunteers were recognised by Dáil Éireann as its legitimate army. Thereafter, the IRA waged a guerrilla campaign against the British occupation of Ireland in the 1919–1921 Irish War of Independence.