The lower house of the parliament ("Oireachtas")of the Republic of Ireland. A member of the house is known as a Teachta Dála ("T.D.") or Dáil Deputy.

Dáil Éireann was originally formed in 1919, by Sinn Féin members who had been elected to the British parliament in Westminster in the 1918 general election. Representing the great majority of Irish voters, they formed Dáil Éireann as an independent parliament, and elected a provisional government with Eamon de Valera as its head. On the same day as the Dáil's first meeting, in Dublin's Mansion House, an attack on a police station in Co. Tipperary heralded the outbreak of the Irish War of Independence.

Dáil Éireann now sits in Leinster House, Merrion Row, Dublin. Its 166 members represent a population of about 4 million, which means that there are fewer citizens per representative in Ireland than in any other European state at present.