| O'Malley, Cathleen | Cathleen O'Malley | Assistant Director | 2022 | 1 | |
| Orlandelli, Paolo | Paolo Orlandelli | Assistant Director | 2019 | 1 | |
| Orsini, Luca | Luca Orsini | Assistant Director | 2015 | 1 | |
| Ostermeier, Thomas | Thomas Ostermeier | Adapter, Director, Translator | 2002 - 2025 | 238 | |
| Olsen, Ragnar | Ragnar Olsen | Adaptation, Translator | 1994 - 2018 | 58 | 1 |
| Osborne, John | John Osborne | Adaptation, Translator | 1972 - 2011 | 8 | 1 |
| Oldenhof, Bouke | Bouke Oldenhof | Adaptation, Translator | 1999 | 2 | |
| Oikonomopoulou, Pepi | Pepi Oikonomopoulou | Adaptation, Director | 2006 | 2 | |
| Oschlag, Jakob | Jakob Oschlag | Adaptation, Director | 1977 - 2001 | 8 | 1 |
| Orsmaa, Taisto-Bertil | Taisto-Bertil Orsmaa | Adaptation, Director | 1983 - 1996 | 3 | 1 |
| O’Rowe, Mark | Mark O’Rowe | Adaptation, Director | 2015 - 2023 | 2 | |
| Olwagen, Christiaan | Christiaan Olwagen | Adaptation, Director | 2015 - 2024 | 6 | |
| O'Reilly, Vincent, A. | Vincent A. O'Reilly | Adaptation, Director | 2012 | 2 | 1 |
| Ochoa, José | José Ochoa | Adaptation, Director | 1974 - 1975 | 10 | |
| Oliboni, Héctor Di | Héctor Di Oliboni | Adaptation, Director | | 2 | |
| Orlikowsky, Wazlaw | Wazlaw Orlikowsky | Adaptation, Choreographer, Director | 1956 - 1964 | 4 | 1 |
| Ollén, Gunnar | Gunnar Ollén | Adaptation | 1947 - 2005 | 2 | 1 |
| Osztovits, Cecilia | Cecilia Osztovits | Adaptation | 2002 | 1 | 1 |
| Oxenvad, Ann Sofie | Ann Sofie Oxenvad | Adaptation | 2003 | 1 | 1 |
| Oakes, Robert | Robert Oakes | Adaptation | 2009 | 1 | |
| O’Hearn, Nigel | Nigel O’Hearn | Adaptation | 2011 - 2016 | 4 | |
| O'Rowe, Mark | Mark O'Rowe | Adaptation | 2016 - 2025 | 2 | 1 |
| O'Horn, Nigel | Nigel O'Horn | Adaptation | 2017 | 1 | |
| Otten, Joe | Joe Otten | Adaptation | 2018 | 1 | |
| Ocano, Armando | Armando Ocano | Adaptation | 1975 - 1980 | 5 | |
| Owen, Gary | Gary Owen | Adaptation | 2025 | 1 | |
| Orak, Aydin | Aydin Orak | Actor, Translator | 2010 | 16 | 2 |
| Otrembowa, Julia | Julia Otrembowa | Actor, Translator | 1883 - 1899 | 4 | |
| Oranowski, Bronisław | Bronisław Oranowski | Actor, Translator | 1907 - 1911 | 3 | |
| O'Lochlainn, Gearoid | Gearoid O'Lochlainn | Actor, Translator | 1928 - 2009 | 2 | |
| Organ, Alex | Alex Organ | Actor, Sound Designer | 2002 | 2 | |
| Olausson, Hilde | Hilde Olausson | Actor, Musician | 1985 - 2015 | 8 | 3 |
| Oscarsson, Ulrika | Ulrika Oscarsson | Actor, Musician | 2001 | 3 | |
| Overbury, Fran | Fran Overbury | Actor, Musical Director | 2001 | 5 | |
| Oertzen, Dietrich v. | Dietrich v. Oertzen | Actor, Dramaturg, Translator | 1981 | 3 | |
| Ohkubo, Ryoichi | Ryoichi Ohkubo | Actor, Director, Translator | 1996 - 2006 | 4 | |
| Oscar, Henry | Henry Oscar | Actor, Director, Producer | 1930 - 1947 | 5 | |
| Oswald, Richard | Richard Oswald | Actor, Director, Producer | 1910 - 1919 | 10 | |
| Otto, Alex | Alex Otto | Actor, Director, Playwright | 1898 - 1934 | 21 | |
| Okornicki, Kazimierz | Kazimierz Okornicki | Actor, Director | 1908 - 1922 | 7 | |
| Ottbert, Otto | Otto Ottbert | Actor, Director | 1876 - 1906 | 7 | |
| Otto, Harald | Harald Otto | Actor, Director | 1896 - 1922 | 55 | 1 |
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