The Irish Free State (Irish: Saorstát Éireann [sˠiːɾˠsˠˈt̪ˠaːt̪ˠ eːɾʲən̪ˠ]; 6 December 1922 – 29 December 1937) was an independent state established in 1922 under the Anglo-Irish Treaty of December 1921. That treaty ended the three-year Irish War of Independence between the forces of the self-proclaimed Irish Republic, the Irish Republican Army (IRA), and British Crown forces.

The Free State was established as a Dominion of the British Commonwealth of Nations. It comprised 26 of the 32 counties of Ireland. Northern Ireland, which comprised the remaining six counties, exercised its right under the Treaty to opt out of the new state. The Free State government consisted of the Governor-General, the representative of the king, and the Executive Council, which replaced both the revolutionary Dáil Government and the Provisional Government set up under the Treaty. W. T. Cosgrave, who had led both of these governments since August 1922, became the first President of the Executive Council. The legislature consisted of Dáil Éireann (the lower house) and Seanad Éireann, also known as the Senate. Members of the Dáil were required to take an Oath of Allegiance, swearing fidelity to the king. The oath was a key issue for opponents of the Treaty, who refused to take the oath and therefore did not take their seats. Pro-Treaty members, who formed Cumann na nGaedheal in 1923, held an effective majority in the Dáil from 1922 to 1927, and thereafter ruled as a minority government until 1932.

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