A by-election was due to be held for a vacancy in Seanad Éireann on Monday, 29 April 2024.[1] The vacancy was caused by the resignation for health reasons of Sinn Féin's Niall Ó Donnghaile from the Administrative Panel on 22 January 2024.[2][3] At the close of nominations on 22 March 2024, only one candidate had been nominated, and Mal O'Hara of the Green Party was elected unopposed.