The June 1927 Irish general election was to elect the 5th Dáil held on Thursday, 9 June following the dissolution of the 4th Dáil on 23 May 1927. It was the first election contested by Fianna Fáil, which had been formed a year earlier when Éamon de Valera, leader of the abstentionist Anti-Treaty Sinn Féin, failed to convince the party to take their seats if and when the Oath of Allegiance were abolished. Most of Sinn Féin's TDs, as well as the bulk of its support, shifted to Fianna Fáil. The impact of this shift saw Sinn Féin all but decimated; it was reduced to five seats. This was for many years the end of the party as a major force in the southern part of the island; it would not win more than 10 seats at an election until 2011, by which time it had undergone fundamental transformation. This election cemented Fianna Fáil as a major party; it and Cumann na nGaedheal/Fine Gael remained the two largest parties in Ireland until 2011.

Fianna Fáil, officially Fianna Fáil – The Republican Party, is a conservative and Christian democratic political party registered in both the Republic of Ireland and Northern Ireland.