Name  | Functions | Event Dates | Events | Resources | ||
|---|---|---|---|---|---|---|
| Robert O’Hearn | Actor, Designer | 1949 - 1950 | 3 | |||
| Nigel O’Hearn | Adaptation | 2011 - 2016 | 4 | |||
| Francis O’Connor | Set Designer | 2023 | 1 | |||
| Will O’Connell | Actor | 2011 | 2 | |||
| Sara O’Connell | Actor, Choreographer, Dancer | 2004 | 4 | |||
| Joan O’Clery | Costume Designer | 2023 | 1 | |||
| Scott O’Brien | Composer | 2001 | 1 | |||
| Peter O’Brien | Costume Designer | 2015 | 1 | |||
| Fergus O’Brien | Sound Designer | 2006 | 9 | |||
| Brad O’Brien | Actor | 2010 | 1 | |||
| Mayrata O'Wisiedo | Actor | 1968 | 1 | |||
| John O'Toole | Actor | 1987 - 2000 | 2 | |||
| Rob O'Sullivan | Actor | 2024 | 1 | |||
| Pat O'Sullivan | Lighting Designer | 1964 | 1 | |||
| Matthew O'Sullivan | Actor | 1984 | 1 | |||
| Mathew O'Sullivan | Actor | 1969 | 1 | |||
| Eugenie O'Sullivan | Director | 1949 | 1 | |||
| Barney O'Sullivan | Actor | 1976 - 1980 | 2 | |||
| Anne O'Sullivan | Actor | 2012 | 1 | |||
| John O'Sullivan IV | Actor | 2013 | 1 | |||
| Ryan O'Shea | Actor | 2008 | 1 | |||
| Milo O'Shea | Actor | 1961 | 1 | |||
| James O'Shea | Actor | 1905 | 1 | |||
| Fiona O'Shaughnessy | Actor | 2008 | 2 | |||
| Finnuala O'Shannon | Actor | 1961 | 1 | |||
| Mark O'Rowe | Adaptation | 2016 - 2025 | 2 | 1 | ||
| Kristen O'Rourke | Actor | 2009 | 1 | |||
| Joan O'Rourke | Actor, Costume Designer | 1945 - 1961 | 4 | |||
| Elle O'Rorke | Actor | 2006 | 1 | |||
| Rachel O'Riordan | Director | 2015 - 2020 | 3 | |||
| Sean O'Riada | Composer | 1961 | 1 | |||
| Vincent A. O'Reilly | Adaptation, Director | 2012 | 2 | 1 | ||
| Sheila O'Reilly | Actor | 1945 | 1 | |||
| Kiera Lee O'Reilly | Dancer | 2024 | 1 | |||
| John O'Reilly | Actor | 1983 | 3 | |||
| James O'Reilly | Actor | 1981 | 2 | |||
| Imelda O'Reilly | Actor | 1990 | 1 | |||
| Genevieve O'Reilly | Actor | 2011 | 1 | 2 | ||
| Ciarán O'Reilly | Director | 2008 | 1 | 1 | ||
| Alpho O'Reilly | Actor | 1948 | 1 | |||
| Honor O'Nians | Designer | 1945 - 1946 | 2 | |||
| Betty O'Nians | Actor | 1954 | 1 | |||