| Opera House | Opera House | United States of America, Pensacola | 1903-10-25 | 1903-10-25 | 1903 | 1 | |
| Ottumwa | Ottumwa | United States of America, Ottumwa | 1903-11-04 | 1903-11-04 | 1903 | 1 | |
| Omaha | Omaha | United States of America, Omaha | 1903-11-05 | 1903-11-05 | 1903 | 1 | |
| Opera House | Opera House | United States of America, San Bernardino | 1903-12-31 | 1908-12-04 | 1903–1908 | 2 | |
| Oviedo | Oviedo | Spain | 1904-- | -- | 1904 | 1 | |
| Opera House | Opera House | United States of America, Altoona | 1904-03-14 | 1904-03-14 | 1904 | 1 | |
| Opera House | Opera House | United States of America, New Castle | 1904-04-29 | 1908-04-11 | 1904–1908 | 2 | |
| Odeon | Odeon | Argentina, Buenos Aires | 1904-06-24 | 1904-06-26 | 1904 | 1 | |
| Opera House | Opera House | United States of America, Bemidji | 1904-09-20 | 1904-09-20 | 1904 | 1 | |
| Opera House | Opera House | United States of America, Hopkinsville | 1904-11-23 | 1904-11-23 | 1904 | 1 | |
| Opera House | Opera House | United States of America, Dixon | 1904-11-30 | 1907-12-21 | 1904–1907 | 2 | |
| Opera House | Opera House | United States of America, New Ulm | 1905-01-15 | 1905-01-15 | 1905 | 1 | |
| Opera House | Opera House | United States of America, McCook | 1905-03-16 | 1905-03-16 | 1905 | 1 | |
| Opera House | Opera House | United States of America, Logan | 1905-04-15 | 1905-04-15 | 1905 | 1 | |
| Opera House | Opera House | United States of America, San Juan | 1905-05-06 | 1905-05-06 | 1905 | 1 | |
| Opera House | Opera House | United States of America, Santa Cruz | 1905-07-28 | 1905-07-28 | 1905 | 1 | |
| Opernhaus Unter den Linden | Opernhaus Unter den Linden | Germany, Berlin | 1905-09-20 | -- | 1905 | 1 | |
| Odeon Theatre | Odeon Theatre | United States of America, St. Louis | 1905-10-04 | 1912-03-27 | 1905–1912 | 2 | |
| Odder Theater | Odder Theater | Denmark, Odder | 1905-11-25 | -- | 1905–1907 | 4 | |
| Orleneff’s Russian Lyceum | Orleneff’s Russian Lyceum | United States of America, New York, East Third Street | 1906-01-03 | -- | 1906 | 1 | |
| Opera House | Opera House | United States of America, New Castle | 1907-03-09 | 1907-03-09 | 1907 | 1 | |
| Odense Folketeater | Odense Folketeater | Denmark, Odense | 1907-10-29 | 1907-11-15 | 1907–1908 | 7 | |
| Olathe Opera House | Olathe Opera House | United States of America, Olathe | 1908-01-31 | 1908-01-31 | 1908 | 1 | |
| Orpheum Theatre | Orpheum Theatre | United States of America, Salt Lake City | 1908-06-13 | 1908-06-13 | 1908 | 1 | |
| Orpheum | Orpheum | United States of America, El Paso | 1908-06-18 | 1908-06-18 | 1908 | 1 | |
| Opera House | Opera House | United States of America, Concord | 1909-04-22 | 1909-04-22 | 1909 | 1 | |
| Orfeó Gracienc | Orfeó Gracienc | Spain, Barcelona, Carrer d'Astúries, 83 (Gràcia) | 1910-07- | -- | 1910–1915 | 2 | |
| Operetten Neues Theater, Central Theater | Operetten Neues Theater, Central Theater | Germany, Leipzig | 1910-08-23 | 1910-08-30 | 1910 | 1 | |
| Overholser Theatre | Overholser Theatre | United States of America, Ardmore | 1910-12-21 | 1910-12-21 | 1910 | 1 | |
| Orăștie | Orăștie | Romania, Orăștie | 1911-02-16 | -- | 1911 | 1 | |
| Odorheiu Secuiesc | Odorheiu Secuiesc | Romania, Odorheiu Secuiesc | 1911-05-09 | -- | 1911 | 1 | |
| Opera House | Opera House | England, Coventry, 4 Hales Street | 1911-09-11 | 1911-09-14 | 1911 | 1 | |
| Opernhaus Graz | Opernhaus Graz | Austria, Graz, Opernring | 1912-05-24 | -- | 1912 | 2 | |
| Ōsaka Chikamatsu-za | Ōsaka Chikamatsu-za (Chikamatsuza Theatre) | Japan, Osaka | 1913-11-21 | 1913-11-25 | 1913 | 1 | |
| Oldenburgisches Staatstheater | Oldenburgisches Staatstheater | Germany, Oldenburg, Theaterwall 28 | 1918-11-30 | 2015-12-20 | 1918–2015 | 12 | |
| Opern- und Schauspielhaus Hannover | Opern- und Schauspielhaus Hannover | Germany, Hannover | 1920-06-21 | -- | 1920–1924 | 2 | |
| Old Vic, The | The Old Vic | England, London, The Cut | 1922-03-06 | 2016-03-19 | 1922–2016 | 11 | |
| Oxford Playhouse | Oxford Playhouse | England, Oxford, 11-12 Beaumont Street | 1924-05-05 | 2018-02-24 | 1924–2018 | 21 | |
| Országos Kamaraszínház | Országos Kamaraszínház | Hungary, Mezőtúr | 1925-09-23 | -- | 1925–1927 | 2 | |
| Oslo | Oslo | Norway, Oslo | 1926-09-12 | 2008-10-02 | 1926–2014 | 10 | |
| Opernhaus Chemnitz | Opernhaus Chemnitz | Germany, Chemnitz, Theaterstraße 2 | 1927-09-27 | -- | 1927–1991 | 4 | |
| Opernhaus Hannover | Opernhaus Hannover | Germany, Hannover, Opernplatz 1 | 1928-03-06 | 1956-12-05 | 1928–1956 | 2 | |
|
|
