Donegal is a parliamentary constituency which has been represented in Dáil Éireann, the lower house of the Irish parliament or Oireachtas, since the 2016 general election.

The constituency elects five deputies (Teachtaí Dála, commonly known as TDs) on the system of proportional representation by means of the single transferable vote (PR-STV).

A by-election was held on 6 November 1980 to fill the vacancy caused by the death on 13 July 1980 of the Fianna Fáil TD Joseph Brennan.

It was won by the Fianna Fáil candidate Clement Coughlan, who died in a road accident in early 1983, triggering a by-election in the Donegal South-West constituency.

A by-election was held on 20 November 1924 to fill the vacancy caused by the resignation on 1 August 1924 of the Cumann na nGaedheal TD Peter Ward.

In Donegal, Sinn Féin's six outgoing TDs from the 2nd Dáil were elected unopposed, Socialist Republican, Jack White having withdrawn his candidacy.

[36] Two had opposed the treaty, and four supported it; they are listed here in alphabetical order At the 1921 general election to the 2nd Dáil, no seats were contested in the 26 counties which became the Irish Free State.