| Name | Position | Party | Constituency |
|---|---|---|---|
| Eoin Ó Broin | Candidate | Sinn Féin | Dublin Mid-West |
| Eoin Ó Broin | Councillor | Independent | Clondalkin |
| Seán Ó Buachalla | Former Representative | Green Party | |
| Diarmaid O Cadhla | Candidate | Independent | Cork North-Central |
| Diarmaid Ó Cadhla | Former Representative | Independent | |
| Caoimhghín Ó Caoláin | Former Representative | Sinn Féin | |
| Marc Ó Cathasaigh | Candidate | Green Party | Waterford |
| Séighin Ó Ceallaigh | Candidate | Sinn Féin | Limerick County |
| Eoghan Ó Ceannabháin | Candidate | People Before Profit Alliance | Dublin Rathdown |
| Naoise Ó Cearúil | Councillor | Fianna Fáil | Maynooth |
| Pádraig Ó Céidigh | Senator | Independent | Taoiseach's Nominee |
| Trevor Ó Clochartaigh | Former Representative | Unknown | |
| Proinsias Ó Conaráin | Candidate | Aontú | Dublin Bay North |
| Cathal Ó Conchúir | Former Representative | Sinn Féin | |
| Cormac Ó Corcoráin | Candidate | Aontú | Galway West |
| Dáithí Ó Cualáin | Councillor | Unknown | Conamara South |
| Seosamh Ó Cualúin | Former Representative | Independent | |
| Éamon Ó Cuív | Candidate | Fianna Fáil | Galway West |
| Tomás Ó Curraoin | Councillor | Independent | Conamara South |
| Brian Ó Domhnaill | Senator | Fianna Fáil | Agricultural Panel |
| Seamus Ó Domhnaill | Former Representative | Fianna Fáil | |
| Niall Ó Donnghaile | Senator | Sinn Féin | Administrative Panel |
| Séafra Ó Faoláin | Councillor | Green Party | Blackrock |
| Sean Ó Fearghail | Former Representative | Fianna Fáil | |
| John Shéamuis Ó Fearraig | Councillor | Sinn Féin | Glenties |
| Oisín Ó Halmhain | Former Representative | Green Party | |
| Donnchadh Ó Laoghaire | Candidate | Sinn Féin | Cork South-Central |
| Aengus Ó Maoláin | Candidate | Social Democrats | Dublin West |
| Naoise Ó Muirí | Councillor | Fine Gael | Clontarf |
| Ruairí Ó Murchú | Candidate | Sinn Féin | Louth |