A by-election was held in the Dáil constituency of Monaghan in Ireland on Tuesday, 27 November 1973. It followed the election of Fianna Fáil TD Erskine H. Childers as president of Ireland on 30 May 1973.
Under Article 12.6.2ð of the Constitution of Ireland, a member of either House of the Oireachtas who is elected as president is deemed to have vacated that seat.
The writ of election to fill the vacancy was agreed by the Dáil on 6 November 1973.
The by-election was won by the Fine Gael candidate Brendan Toal.