| O’Connell, Sara | Sara O’Connell | Actor, Choreographer, Dancer | 2004 | 4 | |
| O’Connell, Will | Will O’Connell | Actor | 2011 | 2 | |
| O’Hearn, Nigel | Nigel O’Hearn | Adaptation | 2011 - 2016 | 4 | |
| O’Hearn, Robert | Robert O’Hearn | Actor, Designer | 1949 - 1950 | 3 | |
| O’Keefe, Brian | Brian O’Keefe | Costume Designer | 2009 | 1 | |
| O’Neill, Michael | Michael O’Neill | Director | 2010 | 1 | |
| O’Riordan, Rachel | Rachel O’Riordan | Director | 2019 - 2020 | 2 | |
| O’Rourke, Rylee | Rylee O’Rourke | Assistant Director, Producer | 2020 - 2022 | 2 | |
| O’Rowe, Mark | Mark O’Rowe | Adaptation | 2015 | 1 | |
| O’Shaughnessy, Hilary | Hilary O’Shaughnessy | Actor | 2011 | 2 | |
| Oak, Girija | Girija Oak | Translator | 2009 | 1 | |
| Oakenleaf, Fingal | Fingal Oakenleaf | Actor | 2008 | 1 | |
| Oaker, Jane | Jane Oaker (Jane Oaker) | Actor | 1904 | 1 | |
| Oakes, Andrew | Andrew Oakes | Actor | 2016 | 1 | |
| Oakes, Robert | Robert Oakes | Adaptation | 2009 | 1 | |
| Oakes, Simeon | Simeon Oakes | Actor | 2012 | 1 | |
| Oakes, Tom | Tom Oakes | Actor | 2004 | 1 | |
| Oakeshott, Owen | Owen Oakeshott | Actor | 2013 - 2014 | 11 | 1 |
| Oakeshott, W., F. | W. F. Oakeshott | Actor | 1925 | 1 | |
| Oakleaf, Donovan | Donovan Oakleaf | Actor | 2018 | 1 | |
| Oakley, Ann | Ann Oakley | Director | 2000 | 1 | |
| Oakley, Martin | Martin Oakley | Lighting Designer | 2021 | 1 | |
| Oanh, Tú | Tú Oanh (Tú Oanh) | Actor | 2006 - 2010 | 2 | |
| Oarcea, Sibylla | Sibylla Oarcea | Actor | 1972 | 4 | |
| Oasheim, Gordon | Gordon Oasheim | Actor | 1951 | 1 | |
| Oaten, James | James Oaten | Actor | 2008 | 1 | |
| Oates, Charlie | Charlie Oates | Director | 2018 | 1 | |
| Oates, Cicely | Cicely Oates | Actor | 1930 | 3 | |
| Oatley, Carl | Carl Oatley | Actor | 1975 | 1 | |
| Obara, Makoto | Makoto Obara | Sound Designer | 1990 | 1 | |
| Obata, Machiko | Machiko Obata | Musician | 1993 | 1 | |
| Obed, Aras | Aras Obed | | | | |
| Obendorf, Lujo | Lujo Obendorf | Costume Designer | 1952 | 1 | |
| Obendorf, Mala | Mala Obendorf | Actor | 1928 | 1 | |
| Obenius, Frej | Frej Obenius | Sound Designer | 2015 | 1 | |
| Oberender, Thomas | Thomas Oberender | Dramaturg | 2003 - 2004 | 6 | |
| Oberhauser, Kendra | Kendra Oberhauser | Actor | 2012 | 1 | |
| Oberhäußer, Frank | Frank Oberhäußer | Assistant Director | 2006 | 1 | |
| Oberheide, Alex | Alex Oberheide | Actor | 2008 | 1 | |
| Oberhof, Johannes | Johannes Oberhof | Actor | 1972 | 2 | |
| Oberhof, Valerie | Valerie Oberhof | Actor | 2002 - 2012 | 6 | |
| Oberhofer, - | - Oberhofer | Actor | 1906 | 1 | |
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