| Ornö | Ornö | Sweden, Ornö | -- | -- | | | |
| Ornans | Ornans | France, Ornans | -- | -- | | | |
| Osimo | Osimo | Italy | -- | -- | | | |
| Oppdal | Oppdal | Norway, Oppdal | -- | -- | | | |
| Ogra | Ogra | Romania, Ogra | -- | -- | | | |
| Opera House | Opera House | United States of America, Wyoming, Wyoming | -- | -- | | | |
| Olivenza | Olivenza | Spain, Olivenza | -- | -- | | | |
| Ocna Sibiului | Ocna Sibiului | Romania, Ocna Sibiului | -- | -- | | | |
| Oravice | Oravice | Slovak Republic, Oravice | -- | -- | | | |
| Oranienburg | Oranienburg | Germany, Oranienburg | -- | -- | | | |
| Ohgawara | Ohgawara | Japan, Ohgawara | -- | -- | | | |
| Odessa | Одеса (Odessa) | Ukraine, Odessa | -- | -- | | | |
| Oulu | Oulu | Finland, Oulu | -- | -- | | | |
| Oituz | Oituz | Romania, Oituz | -- | -- | | | |
| Oddfellows' Hall | Oddfellows' Hall | Australia, Wagga Wagga, Fitzmaurice Street | -- | -- | | | |
| Opole | Opole | Poland, Opole | -- | -- | | | |
| Ostróg | Ostróg | Poland, Ostróg | -- | -- | | | |
| Opera House | Opera House | United States of America, Telluride | -- | -- | | | |
| Odder | Odder | Denmark, Odder | -- | -- | | | |
| Obârşia | Obârşia | Romania, Obârşia | -- | -- | | | |
| Odense Theater | Odense Theater | Denmark, Odense, Sortebrødre Torv | 1876-04-20 | 1899-10-20 | 1876–1901 | 9 | |
| Örebro Teater | Örebro Teater | Sweden, Örebro, Storgatan 1 | 1876-09-23 | 1889-12-14 | 1876–1909 | 8 | |
| Ostend-Theater | Ostend-Theater | Germany, Berlin | 1878-02-06 | -- | 1878–1891 | 5 | |
| Östersund | Östersund | Sweden, Östersund | 1879-- | -- | 1879 | 1 | |
| Oravița | Oravița | Romania, Oravița | 1884-12-08 | 1884-12-23 | 1884–1913 | 3 | |
| Opera Comique Theatre | Opera Comique Theatre | England, London | 1889-07-17 | 1895-03-30 | 1889–1895 | 6 | |
| orrköpings Arbetareförenings teater (Arbisteatern) | orrköpings Arbetareförenings teater (Arbisteatern) | Sweden, Norrköping | 1889-12-16 | -- | 1889 | 1 | |
| Ocna Mureș | Ocna Mureș | Romania, Ocna Mureș | 1890-02-06 | -- | 1890–1911 | 2 | |
| Orosháza | Orosháza | Hungary, Orosháza | 1890-05-12 | -- | 1890–1926 | 6 | |
| Oradea | Oradea | Romania, Oradea | 1890-08-02 | 1936-08-25 | 1890–2012 | 13 | |
| Opera House | Opera House | New Zealand, Wellington, 111/113 Manners Street | 1890-11-28 | 1890-11-29 | 1890 | 1 | |
| Olympic Theatre | Olympic Theatre | United States of America, St. Louis | 1891-01-11 | 1910-04-03 | 1891–1910 | 7 | |
| Opernhaus | Opernhaus | Germany, Frankfurt, Opernplatz 1 | 1892-12-10 | -- | 1892–1940 | 2 | |
| Orpheum | Orpheum | Germany, Munich | 1893-03-08 | -- | 1893–1895 | 3 | |
| Odenkirchen | Odenkirchen | Germany, Odenkirchen | 1893-10-07 | -- | 1893 | 1 | |
| Osnabrücker Stadttheater | Osnabrücker Stadttheater | Germany, Osnabrück, Große Gildewart 7 | 1894-03-29 | 1900-04-26 | 1894–1909 | 7 | |
| Opera House | Opera House | United States of America, Detroit | 1896-02-18 | 1910-09-28 | 1896–1910 | 2 | |
| Osnabrücker Hof | Osnabrücker Hof | Germany, Osnabrück, Kollegienwall 14 | 1896-05-13 | -- | 1896 | 1 | |
| Opera House | Opera House | United States of America, Kentucky, Kentucky | 1899-12-20 | 1903-12-10 | 1899–1903 | 2 | |
| Óbudai Kisfaludy Színház | Óbudai Kisfaludy Színház | Hungary, Budapest | 1900-04-15 | -- | 1900 | 1 | |
| Opština Bečej | Opština Bečej | Serbia, Opština Bečej | 1903-03-11 | -- | 1903 | 1 | |
| Opera House | Opera House | United States of America, Racine | 1903-05-06 | 1903-05-06 | 1903 | 1 | |
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