| Name (3,707) | Functions | Event Dates | Events | Resources |
|---|---|---|---|---|
| Marion O'Dwyer | Actor | 1992 - 1993 | 4 | |
| Simon O'Dwyer | Musician, Singer | 1992 | 1 | |
| Tim O'Dwyer | Actor | 1993 | 1 | |
| Timothy O'Dwyer | Composer, Musician, Musician: Saxophonist, Sound Composer | 1998 - 2006 | 6 | |
| Yael O'Dwyer | Actor | 1977 | 1 | |
| Anne O'Farrell | Actor, Producer | 1955 - 1963 | 4 | |
| Christina O'Farrell | Actor, Prompt, Various | 1957 - 1960 | 3 | |
| Cora O'Farrell | Actor, Singer | 1926 - 1941 | 4 | |
| Dot O'Farrell | Singer | 1923 | 1 | |
| Eileen O'Farrell | Actor | 1922 - 1923 | 3 | |
| Ethan O'Farrell | Mechanist | 2015 | 2 | |
| Joseph O'Farrell | Actor, Creator, Performer | 2005 - 2021 | 11 | |
| Kiane O'Farrell | Actor, Actor and Singer | 2006 - 2022 | 6 | |
| Leanne O'Farrell | Actor, Dancer | 1980 - 1987 | 10 | |
| Talbot O'Farrell | Actor and Singer | 1922 | 1 | |
| Wayne O'Farrell | Actor | 1978 | 1 | |
| Macdara O'Fatharta | Actor | 1990 | 2 | |
| Earnest O'Ferrall | Playwright | 1922 - 1923 | 2 | |
| Robin O'Ferrall | Actor | 1937 | 1 | |
| Eliza O'Flaherty | Actor, Actor and Singer | 1842 - 1851 | 5 | |
| Gem O'Flaherty | Actor | 2010 | 1 | |
| Henry O'Flaherty | Actor, Musician, Playwright | 1842 - 1978 | 3 | |
| Tess O'Flaherty | Actor | 2006 - 2015 | 4 | |
| Eamon O'Flynn | Actor | 2017 | 1 | |
| Emily O'Flynn | Actor | 1998 | 1 | |
| Frances O'Flynn | Actor | 1953 | 1 | |
| Liam O'Flynn | Musician | 1996 | 1 | |
| Mark O'Flynn | Playwright | 1988 - 1999 | 2 | 1 |
| Maureen O'Flynn | Actor | 1999 | 1 | |
| William O'Flynn | Singer | 1949 | 1 | |
| Ryan O'Gara | Lighting Designer | 2021 - 2023 | 4 | |
| Siobhan O'Gara | Actor | 1994 - 2011 | 2 | |
| Melinda O'Garr | Actor | 2004 | 1 | |
| Des O'Gorman | Actor | 2014 | 1 | |
| Eric O'Gorman | Musician | 1992 | 1 | |
| Joyce O'Gorman | Costume Maker | 1980 | 1 | |
| Kevin O'Gorman | Actor, Actor and Singer | 1941 - 1946 | 15 | |
| Lara O'Gorman | Costume Designer, Costume Maker | 2000 | 1 | |
| Michael O'Gorman | Sound Designer | 1998 | 6 | |
| Paul O'Gorman | Musician, Performer, Singer | 1980 | 2 | |
| Sally O'Gorman | Actor | 1971 | 1 | |
| Steph O'Gorman | Actor | 2022 | 1 | |
| Winsome O'Gorman Hughes | Reviewer | 2 | ||
| O'Grady | Singer | 1894 | 1 | |
| Andrew O'Grady | Musician | 2009 - 2010 | 2 | |
| Anne O'Grady | Playwright | 1979 | 1 | |
| Bridget O'Grady | Actor | 1980 | 1 | |
| Catherine O'Grady | Accompanist, Actor | 1969 - 1972 | 4 | |
| Charlene O'Grady | Actor | 1989 | 1 | |
| Charles O'Grady | Assistant to the Director | 2017 | 1 | |
| Dennis O'Grady | Actor | 1960 - 1966 | 3 | |
| Desmond O'Grady | Playwright | 1982 | 1 | 1 |
| Ettie O'Grady | Actor | 1897 | 1 | |
| Frank O'Grady | Actor, Producer | 1932 - 1956 | 8 | |
| Guy O'Grady | Actor, Director | 2006 - 2018 | 15 | |
| Helen O'Grady | Actor | 1968 - 1981 | 10 | |
| Hubert O'Grady | Playwright | |||
| J O'Grady | Dancer | 1987 | 1 | |
| Janet O'Grady | Actor | 1981 | 1 | |
| John O'Grady | Actor | 1948 - 1955 | 11 | |
| Josephine O'Grady | Actor | 1969 - 1974 | 2 | |
| Lucy O'Grady | Musical Director | 2007 | 1 | |
| Maggie O'Grady | Actor | 2000 - 2005 | 7 | |
| Michelle O'Grady | Actor, Performer | 1982 - 1989 | 10 | 1 |
| Molly O'Grady | Costume Designer, Costume Maker | 1985 - 1992 | 2 | |
| Pam O'Grady | Actor, Actor and Singer, Choreographer, Dancer, Director, Performer, Set Designer | 1964 - 2021 | 54 | |
| Patricia O'Grady | Actor | 1961 | 1 | |
| Peter O'Grady | Actor, Lighting Operator/Technician | 1973 - 1992 | 3 | |
| Robert O'Grady | Mechanist | 2008 | 1 | |
| Rosemary O'Grady | Various | 1973 | 1 | |
| Ryan O'Grady | Actor | 2000 | 1 | |
| Rynagh O'Grady | Actor, Playwright | 2006 | 1 | |
| Shaunna O'Grady | Actor, Stage Manager | 1978 - 1993 | 34 | |
| Suellen O'Grady | Reviewer | 1 | ||
| W B O'Grady | Actor | 1893 - 1895 | 11 | |
| William O'Grady | Dancer | 1964 - 1966 | 8 | |
| Jack O'Hagan | Book and Lyrics Librettist, Composer, Lyricist, Performer, Songwriter, Writer | 1926 - 2002 | 12 | 1 |
| James O'Hagan | Actor, Choreographer | 1968 - 1972 | 3 | |
| John O'Hagan | Composer, Musical Director, Musician | 1998 - 2007 | 65 | |
| Megan O'Hagan | Assistant Stage Manager | 2025 | 1 | |
| Paddy O'Hagan | Actor | 1973 - 1975 | 4 | |
| Patrick O'Hagan | Performer, Singer, Singer: Tenor | 1954 - 1973 | 7 | |
| Ruth O'Hagan | Actor | 1971 - 1976 | 4 | |
| Ellie Mae O'Hagen | Performance Artist | 2022 | 1 | |
| O'Halion | Performer | 1900 | 1 | |
| O'Halloran | Performer, Singer | 1898 - 1899 | 2 | |
| A O'Halloran | Set and/or Property Maker | 1971 | 1 | |
| Ann O'Halloran | Actor | 1964 | 1 | |
| Anne O'Halloran | Actor | 1973 - 1978 | 6 | |
| Bernadette O'Halloran | Dancer | 1973 | 1 | |
| Brendan O'Halloran | Actor | 2007 | 1 | |
| Brian O'Halloran | Actor | 1961 | 1 | |
| Bridget O'Halloran | Ensemble Member | 1978 | 1 | |
| Catherine O'Halloran | Actor | 1977 | 1 | |
| David O'Halloran | Actor, Assistant Stage Manager, Chorus, Mechanist, Puppeteer, Reviewer | 1979 - 2008 | 14 | 1 |
| Donald O'Halloran | Producer | 1985 | 1 | |
| Fiona O'Halloran | Make-up Artist | 2006 | 1 | |
| Gail O'Halloran | Actor | 1972 | 2 | |
| Geoff O'Halloran | Actor | 1998 | 1 | |
| Illana O'Halloran | Actor, Performer | 2003 - 2004 | 5 | |