A by-election was held in the Dublin West constituency in Ireland on 27 October 2011 following the death of the Fianna Fáil Teachta Dála (TD) and former Minister for Finance Brian Lenihan, Jnr on 10 June 2011. The 2011 Irish presidential election and two constitutional referendums were held on the same day.
Thirteen candidates contested the by-election. Four were members of Fingal County Council: David McGuinness of Fianna Fáil, Eithne Loftus of Fine Gael, Patrick Nulty of the Labour Party, and Ruth Coppinger of the Socialist Party. The other party candidates were Paul Donnelly of Sinn Féin, Roderic O'Gorman of the Green Party and Peadar Ó Ceallaigh of Fís Nua.
There were six independent candidates: Gary Bermingham, a satirical actor and artist; Benny Cooney, a FÁS employee; Brendan Doris, an architect; Barry Caesar Hunt, a contestant in The Apprentice reality television show in 2010; John Frank Kidd, a retired fire officer; and Jim Tallon, a farmer.