| Ocampo, Paul | Paul Ocampo | Actor, Dancer | 2001 | 2 | |
| Olympios, Spyros | Spyros Olympios | Actor, Dancer | 1935 - 1997 | 10 | |
| Otto, Alexander | Alexander Otto (Alexander Otto) | Actor, Designer | 1919 - 1966 | 7 | |
| Olisah, Paul | Paul Olisah | Actor, Designer | 2002 | 2 | |
| Ovaska, Sulo | Sulo Ovaska | Actor, Designer | 1956 | 2 | |
| O’Hearn, Robert | Robert O’Hearn | Actor, Designer | 1949 - 1950 | 3 | |
| Opgaard, John | John Opgaard | Actor, Designer | 1939 | 2 | |
| Osterberg, Craig | Craig Osterberg | Actor, Designer, Lighting Designer | 2009 | 3 | |
| Okornicki, Kazimierz | Kazimierz Okornicki (Kazimierz Okornicki) | Actor, Director | 1908 - 1922 | 7 | |
| Ottbert, Otto | Otto Ottbert (Otto Ottbert) | Actor, Director | 1876 - 1906 | 7 | |
| Otto, Harald | Harald Otto (Harald Otto) | Actor, Director | 1896 - 1922 | 55 | |
| Ourth, Georges | Georges Ourth (Georges Ourth) | Actor, Director | 1978 - 1984 | 2 | |
| Ording, Jørn | Jørn Ording (Jørn Ording) | Actor, Director | 1938 - 1978 | 69 | |
| O'Connell, Deirdre | Deirdre O'Connell (Deirdre O'Connell) | Actor, Director | 1971 - 1985 | 6 | |
| Oskui, Mahin | Mahin Oskui (Mahin Oskui) | Actor, Director | 1959 | 2 | |
| Otto, Herr | Herr Otto (Herr Otto) | Actor, Director | 1878 | 2 | |
| Ozoliņš, Pēteris | Pēteris Ozoliņš (Pēteris Ozoliņš) | Actor, Director | 1889 - 1912 | 5 | |
| Outram, Leonard | Leonard Outram (Leonard Outram) | Actor, Director | 1891 - 1897 | 7 | |
| Odemar, Fritz | Fritz Odemar (Fritz Odemar) | Actor, Director | 1893 - 1934 | 5 | |
| Osmarr, Otto | Otto Osmarr (Otto Osmarr) | Actor, Director | 1889 - 1919 | 23 | |
| Oikonomou, Thomas | Thomas Oikonomou (Thomas Oikonomou) | Actor, Director | 1902 - 1926 | 121 | |
| Ognjanov, Sava | Sava Ognjanov (Sava Ognjanov) | Actor, Director | 1905 - 1928 | 8 | |
| Ones, Arvid | Arvid Ones (Arvid Ones) | Actor, Director | 1983 - 2004 | 22 | |
| Olin, Wilhelm | Wilhelm Olin (Wilhelm Olin) | Actor, Director | 1891 - 1919 | 2 | |
| Osis, Jānis | Jānis Osis | Actor, Director | 1921 - 1943 | 5 | |
| Oden, Christopher | Christopher Oden | Actor, Director | 1984 - 2001 | 6 | |
| Oliver, Barbara | Barbara Oliver | Actor, Director | 2006 - 2010 | 3 | |
| Olsen, Arne, Thomas | Arne Thomas Olsen | Actor, Director | 1955 - 1963 | 19 | |
| Olsen, Clifford, R. | Clifford R. Olsen | Actor, Director | 1963 | 2 | |
| O'Connell, Dan | Dan O'Connell | Actor, Director | 1943 - 1961 | 2 | |
| Orell, Heinrich | Heinrich Orell | Actor, Director | 1911 | 2 | |
| Orlenev, Pavel | Pavel Orlenev | Actor, Director | 1903 - 1923 | 7 | |
| Otto, Alex | Alex Otto (Alex Otto) | Actor, Director, Playwright | 1898 - 1934 | 21 | |
| Oscar, Henry | Henry Oscar (Henry Oscar) | Actor, Director, Producer | 1930 - 1947 | 5 | |
| Oswald, Richard | Richard Oswald (Richard Oswald) | Actor, Director, Producer | 1910 - 1919 | 10 | |
| Ohkubo, Ryoichi | Ryoichi Ohkubo | Actor, Director, Translator | 1996 - 2006 | 4 | |
| Oertzen, Dietrich v. | Dietrich v. Oertzen | Actor, Dramaturg, Translator | 1981 | 3 | |
| Overbury, Fran | Fran Overbury | Actor, Musical Director | 2001 | 5 | |
| Olausson, Hilde | Hilde Olausson (Hilde Olausson) | Actor, Musician | 1985 - 2015 | 8 | 2 |
| Oscarsson, Ulrika | Ulrika Oscarsson | Actor, Musician | 2001 | 3 | |
| Organ, Alex | Alex Organ (Alex Organ) | Actor, Sound Designer | 2002 | 2 | |
| Orak, Aydin | Aydin Orak (Aydin Orak) | Actor, Translator | 2010 | 16 | 2 |
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