A by-election is due to be held in the Dáil constituency of Galway West in Ireland in 2026, to fill the vacancy left by the election of Catherine Connolly as president of Ireland. 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. Connolly was declared elected as president on 25 October 2025. According to the Electoral (Amendment) Act 2011, the writ for the by-election must be issued within six months of the vacancy. In February 2026, Taoiseach Micheál Martin said the by-election would be held in May, together with the 2026 Dublin Central by-election.
The Dáil constituency of Galway West elects five TDs. It spans the western half of County Galway, taking in Galway city, the Galway Gaeltacht, Oranmore, Oughterard and Clifden. At the 2024 general election, Galway West elected one Sinn Féin, one Fianna Fáil, one Fine Gael and two independent TDs (Catherine Connolly and Noel Grealish).
On 28 October 2025, Independent Ireland stated that councillor Noel Thomas, formerly of Fianna Fáil, was selected as their candidate for the by-election. The Green Party selected former councillor Niall Murphy as their candidate on 6 December 2025.
Independent candidates who indicated an intention to stand during January 2026 included independent councillor Thomas Welby, formerly of the Progressive Democrats and the former campaign manager for Catherine Connolly, Sheila Garrity. During a party conference in November 2025, the Labour Party indicated that it would contest the election, and local councillor Helen Ogbu was selected as the party's candidate in January 2026.
Social Democrats leader Holly Cairns said that her party would also stand its own candidate and, in February 2026, MÃÂde Nic Fhionnlaoich (a parliamentary assistant to TD Sinéad Gibney) was selected as its candidate. Aontú selected Orla Nugent as their candidate in February 2026.
Senator Seán Kyne was selected as the Fine Gael candidate on 22 February 2026. On 24 February 2026 People Before Profit announced Denman Rooke as their candidate.
Despite speculation about a joint left ticket, Sinn Féin leader Mary Lou McDonald said her party would stand its own candidate, but she reportedly stated that she would like to see a transfer pact between left-wing candidates. On 19 March 2026 the party selected former City Councillor and Galway West branch chairperson Mark Lohan as its candidate.
On 25 March 2026, Mike Cubbard, an independent councillor and Mayor of Galway since June 2025, declared that he would contest the election.
On 29 March 2026, Oranmore-based councillor Cillian Keane was selected as the Fianna Fáil candidate.
Following the election of Catherine Connolly as president of Ireland, a new Galway-based political group called Tonn na Clé (Left Wave) began promoting a "vote left, transfer left" pact. In March 2026, it was reported that six candidates in Galway West proposed to agree a "Vote Left, Transfer Left" pact. The potential agreement, facilitated by Tonn na Clé, involves candidates from the Labour Party, Sinn Féin, the Green Party, the Social Democrats, People Before Profit, and Garitty, who is an independent.
It was also reported in March 2026 that there would be no Irish language candidate debates on TG4 or Raidió na Gaeltachta as only three candidates â Kyne, Nugent, and Nic Fhionnlaoich â are "sufficiently fluent" in Irish.