| Seán 'ac Dhonncha | Person | Male | Ireland | 1919-10-02 | County Galway, Connaught , Ireland | 1996-12-14 | | |
| Johnny ‘Nóra Aodha’ | Person | | County Cork, Munster, Ireland | 1886 | | 1928 | | |
| "The Art Crimes Band" | Group | | United Kingdom | 2011 | Ireland | | | |
| Kraft (IE) | | | Ireland | | | | | |
| (retards) | Group | | Ireland | 2004-12-31 | Dublin, County Dublin, Leinster, Ireland | [unknown] | | |
| (sic) | Group | | Ireland | 1996 | Dublin, County Dublin, Leinster, Ireland | 1999 | Dublin, County Dublin, Leinster, Ireland | |
| [R]evolution Of A Sun | Group | | Ireland | | Cork, County Cork, Munster, Ireland | | | |
| The #1s | Group | | Dublin, County Dublin, Leinster, Ireland | 2011-06-06 | Killiney, County Dublin, Leinster, Ireland | | | |
| +DuLT+ | Person | Female | Ireland | | | | | |
| ≽ܫ≼ | Person | | Ireland | | | | | |
| ◉ | Person | | Ireland | | | | | |
| 0phelia | Person | Female | Cork, County Cork, Munster, Ireland | | | | | |
| The 2 Johnnies | Group | | Ireland | 2017 | | | | |
| 2caves | Person | Male | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | 1994-02-12 | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| 2haf | | | Dublin, County Dublin, Leinster, Ireland | | | | | |
| 3 on the Bund | Group | | Ireland | 2019-03 | | | | |
| 3D Shark | Group | | Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | 2010 | | | | |
| 3epkano | Group | | Dublin, County Dublin, Leinster, Ireland | 2004 | Dublin, County Dublin, Leinster, Ireland | | | |
| 4AM Club | Group | | Northern Ireland, United Kingdom | | | | | |
| The 4th State | | | Ireland | | | | | |
| 5daysandcounting | Group | | Ireland | | County Dublin, Leinster, Ireland | | | |
| 5th Gear Music | Group | | Dublin, County Dublin, Leinster, Ireland | 2022-03-08 | | | | |
| 7.5 Tonnes of Beard | Group | | Northern Ireland, United Kingdom | | | | | |
| 7una | Person | Female | Dublin, County Dublin, Leinster, Ireland | | | | | |
| 9thchord | Person | Male | Galway, County Galway, Connaught , Ireland | | Barcelona, Barcelona , Catalunya , Spain | | | |
| 10 foot clown | Group | | Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | 2012 | Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| 12 Gauge Outrage | | | Ireland | | Ireland | | | |
| 20 Bulls Each | Group | | Dublin, County Dublin, Leinster, Ireland | | | | | |
| 21 Demands | Group | | Ireland | 2005 | | | | |
| 49th & Main | Group | | Kilkenny, County Kilkenny, Leinster, Ireland | | Kilkenny, County Kilkenny, Leinster, Ireland | | | |
| 66e | Group | | Dublin, County Dublin, Leinster, Ireland | 2002 | | | | |
| 79Cortinaz | Group | | Ireland | 2003 | | | | |
| 80s Icon Show | Group | | Ireland | | | | | |
| 93 Acres | Person | Male | Ireland | | | | | |
| 100 Sparrows | Person | Male | Dublin, County Dublin, Leinster, Ireland | 1977-05-27 | Dublin, County Dublin, Leinster, Ireland | | | |
| 100% Pure Irish Dance | Group | | Ireland | | | | | |
| 666cmg | Person | Male | Ireland | | | | | |
| 1000 Beasts | Person | Male | Ireland | | | | | |
| 1000 Drunken Nights | Group | | United Kingdom | | Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| 516899c279d7072a1598b59bbd2360d5 | Person | | Northern Ireland, United Kingdom | | | | | |
| A Bad Diana | Person | Female | Ireland | | | | | |
| A Clatter and Drone | Group | | Dublin, County Dublin, Leinster, Ireland | | | | | |
| A House | Group | | Ireland | 1985 | Dublin, County Dublin, Leinster, Ireland | 1997 | | |
| A Lazarus Soul | Group | | Dublin, County Dublin, Leinster, Ireland | 2001-04-01 | | | | |
| A Plastic Rose | Group | | Nottingham, England, United Kingdom | 2006-10-01 | Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| A Ritual Sea | Group | | Dublin, County Dublin, Leinster, Ireland | | Dublin, County Dublin, Leinster, Ireland | | | |
| A-Political | Group | | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | | | |
| A.J Roland | Person | Male | Northern Ireland, United Kingdom | | | | | |
| A.N.J.A. | Person | Female | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | 1993-09-07 | Ravensburg, Baden-Württemberg, Germany | | | 5 |
| A.2.Z | Person | Male | Ireland | | | | | |
| A3 | Group | | Cork, County Cork, Munster, Ireland | 2023-03-08 | Cork, County Cork, Munster, Ireland | | | 4 |
| A10Sín | Person | Male | Galway, County Galway, Connaught , Ireland | | | | | |
| AaronC | Person | Male | Drogheda, County Louth, Leinster, Ireland | 2006 | | | | |
| AaronMusic | Group | | Ireland | 2022-10-09 | Ireland | | | 5 |
| ABA | Other | | Ireland | | | | | |
| Abaddon Incarnate | Group | | Ireland | 1994 | Dublin, County Dublin, Leinster, Ireland | | | 5 |
| ABBA Sensations | Group | | Northern Ireland, United Kingdom | 2011 | Northern Ireland, United Kingdom | | | |
| ABBA‐esque | Group | | Ireland | 1996-01 | County Dublin, Leinster, Ireland | | | |
| Abbacaxi | Person | Male | Dublin, County Dublin, Leinster, Ireland | 1992-01-30 | | | | |
| Ashley Abbedeen | Person | Female | Ireland | | | | | |
| The Abbey Céilí Band | Group | | County Cork, Munster, Ireland | 1995 | County Cork, Munster, Ireland | | | |
| Abbeyfolk | Group | | Ireland | | | | | |
| Abbotoir | Group | | | 2013 | Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| Thomas Kingsmill Abbott | Person | Male | | 1829-03-26 | Dublin, County Dublin, Leinster, Ireland | 1913-12-18 | | |
| Aaron Abernethy | Person | Male | Northern Ireland, United Kingdom | | | | | |
| Abhor | | | Ireland | 1994 | Cork, County Cork, Munster, Ireland | [unknown] | | |
| Able Archer | Group | | Dublin, County Dublin, Leinster, Ireland | | Dublin, County Dublin, Leinster, Ireland | | | |
| Aborted Earth | Group | | Dublin, County Dublin, Leinster, Ireland | 2018 | Dublin, County Dublin, Leinster, Ireland | | | |
| Absolutist | Group | | Ireland | | | | | |
| Abuse Potential | | | Ireland | | | | | |
| ABYSM | Person | | Cork, County Cork, Munster, Ireland | | | | | |
| Abyss Gazes | Group | | Poland | 2018 | Clonmel, County Tipperary, Munster, Ireland | | | |
| Abyssery | Group | | Dublin, County Dublin, Leinster, Ireland | 2023 | | | | |
| Acacia | Group | | Northern Ireland, United Kingdom | | | | | |
| The Academic | Group | | Ireland | 2013-11 | | | | |
| Cvartetul Academica | Group | | Ireland | 1967 | București , Romania | [unknown] | | |
| Accidents in the Workplace | Group | | Dundalk, County Louth, Leinster, Ireland | | Dundalk, County Louth, Leinster, Ireland | | | |
| Aces Wild | Group | | Ireland | 1999 | Dublin, County Dublin, Leinster, Ireland | | | |
| The Achill Sound | Group | | Ireland | | | | | |
| Acid Age | Group | | Northern Ireland, United Kingdom | 2013 | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| Acid-Nab | Person | Male | Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | | | 5 |
| Acidtone | Group | | Northern Ireland, United Kingdom | 2002-09 | Downpatrick, Down, County Down, Northern Ireland, United Kingdom | [unknown] | | |
| Acme | Group | | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | | | |
| Acrid Nebula | Group | | Ireland | 2007 | | 2011 | | |
| Acrobat | Group | | Dublin, County Dublin, Leinster, Ireland | 2012-01-01 | Dublin, County Dublin, Leinster, Ireland | | | |
| Tom Acton | Person | Male | Dublin, County Dublin, Leinster, Ireland | | | | | |
| Ad Astra Chamber Orchestra | Orchestra | | Dublin, County Dublin, Leinster, Ireland | 2019 | | | | |
| Ādam | Person | Male | Ireland | | | | | |
| Adam's Curse | Group | | Ireland | | | | | 3 |
| David Adams | Person | Male | Ireland | | Dublin, County Dublin, Leinster, Ireland | | | |
| Desy Adams | Person | | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| Gerry Adams | Person | Male | | 1948-10-06 | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | | | |
| Robbie Adams | Person | Male | Los Angeles, California, United States | | Dublin, County Dublin, Leinster, Ireland | | | |
| Sebastian Adams | Person | Male | Ireland | 1991 | | | | |
| Adaneya | Person | | Galway, County Galway, Connaught , Ireland | | | | | |
| Adebisi Shank | Group | | Ireland | 2006-08 | Wexford, County Wexford, Leinster, Ireland | | | 3 |
| Adelante | Group | | Ireland | | | | | |
| Jordan Adetunji | Person | Male | Belfast, Belfast , County Antrim, County Down, Northern Ireland, United Kingdom | 1999-02-25 | London , England, United Kingdom | | | |
| Adeyhawke | Person | Male | Dublin, County Dublin, Leinster, Ireland | | | | | |
| Johnny Adger | Person | Male | Ireland | | | | | |