| Ojamaa, Pekka | Pekka Ojamaa | Costume Designer, Designer | 1990 - 2001 | 9 | |
| Oka, Mizuho | Mizuho Oka | Actor | 1928 | 1 | |
| Okopiński, Marek | Marek Okopiński | Actor | 1958 | 1 | |
| Okornicki, Kazimierz | Kazimierz Okornicki | Actor, Director | 1908 - 1922 | 7 | |
| Okraska, Paweł | Paweł Okraska | Actor | 1999 | 1 | |
| Okura, Shonosuke | Shonosuke Okura | Actor | 2005 - 2013 | 14 | |
| Olchowska, (Nuna) Młodziejowska | (Nuna) Młodziejowska Olchowska | Actor | 1905 - 1907 | 2 | |
| Olderkjær, Stian | Stian Olderkjær | Actor | 2006 | 1 | |
| Olenicki, Manfred | Manfred Olenicki | Actor | 1995 - 1998 | 3 | |
| Oleś, Marcin | Marcin Oleś | Composer | 2006 - 2009 | 7 | |
| Olschansky, Aage | Aage Olschansky | Actor | 1981 | 1 | |
| Olsen, Augusta | Augusta Olsen | Actor | 1907 | 10 | |
| Ongjerth, Zsuzsanna | Zsuzsanna Ongjerth | Actor | 1960 | 1 | |
| Ono, Masutaro | Masutaro Ono | Actor | 1913 | 1 | |
| Ono, Mizuho | Mizuho Ono | Actor | 1997 | 1 | |
| Onslow, Michael | Michael Onslow | Actor | 1999 | 30 | |
| Opsann, Aksel | Aksel Opsann | Actor | 1900 - 1928 | 66 | |
| Oranjehotel, Het | Het Oranjehotel | | | | |
| Orberg, Lisa | Lisa Orberg | Actor | 1974 | 1 | |
| Orchis, Isella | Isella Orchis | Actor | 1993 | 2 | |
| Organ, Alex | Alex Organ | Actor, Sound Designer | 2002 | 2 | |
| Orlik, Stanisław | Stanisław Orlik | Actor | 1904 - 1924 | 4 | |
| Orliński, Janusz | Janusz Orliński | Actor | 1904 - 1916 | 9 | |
| Orloff, Penny | Penny Orloff | Actor | 1982 | 1 | |
| Orlovsky, Claudia | Claudia Orlovsky | Choreographer | 1998 | 1 | |
| Orme, Michael | Michael Orme | Director, Producer | 1930 - 1936 | 5 | |
| Ormond, Claire | Claire Ormond | Actor | 1993 | 1 | |
| Orr, Diane | Diane Orr | Actor | 1979 | 1 | |
| Orth, Elisabeth | Elisabeth Orth | Actor | 1971 - 1995 | 6 | |
| Osborn, Elmar | Elmar Osborn | Actor | 1955 | 1 | |
| Osborne, Dorithy | Dorithy Osborne | Actor | 1943 | 1 | |
| Osborne, Si | Si Osborne | Actor | 2001 | 2 | |
| Oscar, Henry | Henry Oscar | Actor, Director, Producer | 1930 - 1947 | 5 | |
| Osswald, Leni | Leni Osswald | Costume Designer | 1955 - 1962 | 2 | |
| Ostermayer, Christine | Christine Ostermayer | Actor | 1965 - 1969 | 3 | |
| Oswald, Axsel | Axsel Oswald | Actor | 1936 - 1937 | 2 | |
| Ott, Günther | Günther Ott | Actor | 1931 | 1 | |
| Ottavino, John | John Ottavino | Actor | 1997 | 1 | |
| Ottbert, Otto | Otto Ottbert | Actor, Director | 1876 - 1906 | 7 | |
| Otto, Alexander | Alexander Otto | Actor, Designer | 1919 - 1966 | 7 | |
| Otto, Pavel | Pavel Otto | Actor | 1957 | 1 | |
| Otto, Wilfried | Wilfried Otto | Designer | 1958 | 1 | |
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