The government of the 1st Dáil was the executive of the unilaterally declared Irish Republic. At the 1918 Westminster election, candidates for Sinn Féin stood on an abstentionist platform, declaring that they would not remain in the Parliament of the United Kingdom but instead form a unicameral, revolutionary parliament for Ireland called Dáil Éireann.

The First Dáil was Dáil Éireann as it convened from 1919 to 1921. It was the first meeting of the unicameral parliament of the revolutionary Irish Republic. In the December 1918 election to the Parliament of the United Kingdom, the Irish republican party Sinn Féin won a landslide victory in Ireland. In line with their manifesto, its MPs refused to take their seats, and on 21 January 1919 they founded a separate parliament in Dublin called Dáil Éireann. They declared Irish independence, ratifying the Proclamation of the Irish Republic that had been issued in the 1916 Easter Rising, and adopted a provisional constitution.