| Olivero, Franco | Franco Olivero | Actor | 1986 - 1987 | 3 | |
| Orléans, Sabine | Sabine Orléans | Actor | 1994 | 3 | |
| Ovanessian, Arby | Arby Ovanessian | Costume Designer, Designer, Director | 1970 | 3 | 1 |
| O'Riordan, Rachel | Rachel O'Riordan | Director | 2015 - 2020 | 3 | |
| Omar, Hersh | Hersh Omar | Musician | 2013 - 2014 | 3 | |
| Orlando, Carlo | Carlo Orlando | Assistant Director | 2021 | 3 | |
| Olding, Francesca | Francesca Olding | Actor | 1980 | 3 | |
| Olding, Federico | Federico Olding | Actor | 1980 | 3 | |
| Obinu, Gianfranco Onatziro | Gianfranco Onatziro Obinu | Actor | 2015 - 2019 | 3 | |
| Ohnemus, Chris | Chris Ohnemus | Dramaturg | 1999 - 2000 | 2 | |
| Oikonomopoulou, Pepi | Pepi Oikonomopoulou | Adaptation, Director | 2006 | 2 | |
| Olchowska, (Nuna) Młodziejowska | (Nuna) Młodziejowska Olchowska | Actor | 1905 - 1907 | 2 | |
| Ollén, Gunnar | Gunnar Ollén | Adaptation | 1947 - 2005 | 2 | 1 |
| Omdal, Odin Hørthe | Odin Hørthe Omdal | Actor | 1995 - 1999 | 2 | 1 |
| Organ, Alex | Alex Organ | Actor, Sound Designer | 2002 | 2 | |
| Osborne, Si | Si Osborne | Actor | 2001 | 2 | |
| Osswald, Leni | Leni Osswald | Costume Designer | 1955 - 1962 | 2 | |
| Oswald, Axsel | Axsel Oswald | Actor | 1936 - 1937 | 2 | |
| Otto, Miranda | Miranda Otto | Actor | 2002 - 2015 | 2 | 1 |
| Ourth, Georges | Georges Ourth | Actor, Director | 1978 - 1984 | 2 | |
| Oittinen, Tytti | Tytti Oittinen | Director | 1992 - 1994 | 2 | 1 |
| Osterberger, - | - Osterberger | Actor | 1971 | 2 | |
| Ovčinnikova, O. | O. Ovčinnikova | Actor | 1999 - 2000 | 2 | |
| Olenina, E. | E. Olenina | Dancer | 1999 - 2000 | 2 | |
| O'Brien, Dan | Dan O'Brien | Designer, Lighting Designer | 2008 | 2 | |
| Oanh, Tú | Tú Oanh | Actor | 2006 - 2010 | 2 | |
| O'Kane, Nancy | Nancy O'Kane | Actor | 1952 - 1961 | 2 | |
| Oitana, Ricky | Ricky Oitana | Actor | 1996 | 2 | |
| O'Brien, James | James O'Brien | Actor | 1957 - 1971 | 2 | |
| O'Connell, Patricia | Patricia O'Connell | Actor | 1975 - 2000 | 2 | |
| Oosthout, Nelly | Nelly Oosthout | Actor | 1928 - 1930 | 2 | |
| Oppenheim, Yoni | Yoni Oppenheim | Director, Producer | 2011 | 2 | 1 |
| Oskui, Mahin | Mahin Oskui | Actor, Director | 1959 | 2 | 1 |
| Otto, Erich | Erich Otto | Actor | 1920 - 1921 | 2 | |
| O'Neill, Chris | Chris O'Neill | Designer, Lighting Designer | 2011 | 2 | |
| Oraker, Rutledge | Rutledge Oraker | Actor | 1932 | 2 | |
| Ogawa, Toshiro | Toshiro Ogawa | Lighting Designer | 1964 - 1981 | 2 | |
| O'Reilly, James | James O'Reilly | Actor | 1981 | 2 | |
| Otto, Herr | Herr Otto | Actor, Director | 1878 | 2 | |
| Ott, Mr. | Mr. Ott | Actor | 1889 | 2 | |
| Oberle, Thomas | Thomas Oberle | Actor | 1891 - 1904 | 2 | |
| Olbrich, Irmgard | Irmgard Olbrich | Actor | 1893 - 1901 | 2 | |
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