| Oberländer, Hans | Hans Oberländer | Director | 1904 - 1908 | 2 | |
| Orliński, Janusz | Janusz Orliński | Actor | 1904 - 1916 | 9 | |
| Orlik, Stanisław | Stanisław Orlik | Actor | 1904 - 1924 | 4 | |
| Onno, Ferdinand | Ferdinand Onno | Actor | 1904 - 1938 | 9 | |
| Otis, Edith | Edith Otis | Actor | 1905 | 1 | |
| O'Shea, James | James O'Shea | Actor | 1905 | 1 | |
| Ottolini, Piero | Piero Ottolini | Translator | 1905 - 1906 | 4 | 1 |
| Olchowska, (Nuna) Młodziejowska | (Nuna) Młodziejowska Olchowska | Actor | 1905 - 1907 | 2 | |
| Ognjanov, Sava | Sava Ognjanov | Actor, Director | 1905 - 1928 | 8 | |
| Orloff, Ida | Ida Orloff | Actor | 1905 - 1942 | 26 | |
| Olsen, Ottilie | Ottilie Olsen | Actor | 1906 | 1 | |
| Olive, Edyth | Edyth Olive | Actor | 1906 | 1 | 1 |
| Orchowski, Walter | Walter Orchowski | Actor | 1906 | 1 | |
| Onsøjen, Ole | Ole Onsøjen | Musical Director | 1906 | 1 | |
| Oberhofer, - | - Oberhofer | Actor | 1906 | 1 | |
| O'Connor, Herbert | Herbert O'Connor | Actor | 1906 | 1 | |
| Osmond, Clara | Clara Osmond | Actor | 1906 - 1907 | 3 | |
| Otto, Marg. | Marg. Otto | Actor | 1906 - 1908 | 3 | |
| Olasz, Pál | Pál Olasz | Actor | 1906 - 1908 | 4 | |
| Oland, Warner | Warner Oland | Actor | 1906 - 1908 | 5 | 1 |
| Oster, Teresina | Teresina Oster | Actor | 1906 - 1909 | 4 | |
| Ottmay, Georg | Georg Ottmay | Actor | 1906 - 1961 | 8 | |
| Ozerova, E A | E A Ozerova | Actor | 1907 | 1 | |
| Olsen, Augusta | Augusta Olsen | Actor | 1907 | 10 | |
| Oranowski, Bronisław | Bronisław Oranowski | Actor, Translator | 1907 - 1911 | 3 | |
| Orloff, Nicholas | Nicholas Orloff | Actor | 1908 | 1 | 1 |
| Owen, William | William Owen | Actor | 1908 | 1 | 1 |
| Ogińska, Antonina | Antonina Ogińska | Actor | 1908 - 1910 | 3 | |
| Okornicki, Kazimierz | Kazimierz Okornicki | Actor, Director | 1908 - 1922 | 7 | |
| Oehlmann, Hans | Hans Oehlmann | Actor | 1909 | 1 | |
| O'Neil, Barry | Barry O'Neil | Director | 1909 | 1 | |
| Okada, Saburonosuke | Saburonosuke Okada | Designer | 1909 | 1 | |
| Ostužev, Aleksandr, Alekseevic | Aleksandr Alekseevic Ostužev | Actor | 1909 | 1 | |
| Osanai, Kaoru | Kaoru Osanai | Director | 1909 - 1928 | 6 | 1 |
| Olden, Arno W. | Arno W. Olden | Actor | 1910 | 1 | |
| Odzhakov, Zhivko | Zhivko Odzhakov | Actor | 1910 | 1 | |
| Obreschkov, Todor | Todor Obreschkov | Actor | 1910 | 1 | |
| Odzhakova, Jurija | Jurija Odzhakova | Actor | 1910 | 1 | |
| Ostrowska, Franciszka | Franciszka Ostrowska | Actor | 1910 | 2 | |
| Otto, Karl | Karl Otto | Actor | 1910 - 1911 | 2 | |
| Osterloh, Hildegard | Hildegard Osterloh | Actor | 1910 - 1916 | 15 | |
| Oswald, Richard | Richard Oswald | Actor, Director, Producer | 1910 - 1919 | 10 | |
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