| Immenstadt | Immenstadt | Germany, Immenstadt | -- | -- | | | |
| Islington | Islington | England, London | -- | -- | | | |
| Iaşi | Iaşi | Romania, Iaşi | -- | -- | | | |
| Iacobeni | Iacobeni | Romania, Iacobeni | -- | -- | | | |
| Ipswich | Ipswich | England, Ipswich | -- | -- | | | |
| Ianca | Ianca | Romania, Ianca | -- | -- | | | |
| Iitti | Iitti | Finland, Iitti | -- | -- | | | |
| Ineu | Ineu | Romania, Ineu | -- | -- | | | |
| Ileana | Ileana | Romania, Ileana | -- | -- | | | |
| Izmail | Izmail | Ukraine, Izmail | -- | -- | | | |
| Irazee | Irazee | United States of America, Irazee | -- | -- | | | |
| Interimstheater Brünn | Interimstheater Brünn | Czech Republic, Brno, Žerotín square | 1880-01-01 | -- | 1880 | 1 | |
| Irving Place Theatre | Irving Place Theatre | United States of America, New York, East 15th Street | 1897-04-12 | 1913-11-12 | 1897–1918 | 9 | |
| Ironwood Opera House | Ironwood Opera House | United States of America, Ironwood | 1899-02-24 | 1899-02-24 | 1899 | 1 | |
| Istanbul | Istanbul | Turkey, Istanbul | 1900-12- | 2014-05-29 | 1900–2014 | 5 | |
| Intimes Theater | Intimes Theater | Germany, Nürnberg, Wolfsschlucht | 1901-01-03 | -- | 1901–1912 | 7 | |
| Ida Aalbergin kiertue | Ida Aalbergin kiertue | Finland | 1903-- | -- | 1903–1908 | 7 | |
| Imperial Theatre | Imperial Theatre | England, Westminster, London, Tothill Street | 1903-01-25 | 1903-01-26 | 1903 | 2 | |
| Izmir | Izmir | Turkey, Izmir | 1903-11- | 2013-05- | 1903–2012 | 2 | |
| Illinois Theatre | Illinois Theatre | United States of America, Rock Island | 1904-03-15 | 1904-03-15 | 1904 | 1 | |
| Imperial Theatre | Imperial Theatre | United States of America, Saint-Louis | 1904-11-17 | 1904-11-17 | 1904 | 1 | |
| Ivano-Frankivsk | Ivano-Frankivsk | Ukraine, Ivano-Frankivsk | 1907-03- | 1907-04- | 1907 | 1 | |
| IATC/UNATC ( National University of Theatre and Film "I.L. Caragiale") | IATC/UNATC ( National University of Theatre and Film "I.L. Caragiale" ) | Romania, Bucharest, Matei Voievod Street 75-77 | 1907-05-26 | 1907-05-27 | 1907–2015 | 9 | |
| Illinois Theatre | Illinois Theatre | United States of America, Chicago, 65 E. Jackson Boulevard | 1908-01-31 | -- | 1908–1927 | 2 | |
| Imperial Theatre | Imperial Theatre | Canada, Vancouver | 1908-07-09 | 1908-07-09 | 1908 | 1 | |
| Intimes Theater | Intimes Theater | Switzerland, Bern | 1909-10-21 | 1909-12-01 | 1909 | 1 | |
| Innsjön | Innsjön | Sweden, Innsjön | 1911-07-03 | 1911-07-04 | 1911 | 1 | |
| Intima Teatern | Intima Teatern | Sweden, Stockholm, Barnhusgatan 20 | 1912-11-01 | 1919-03-14 | 1912–1919 | 3 | |
| Irish Theatre, The | The Irish Theatre | Ireland, Dublin | 1917-04-23 | 1918-02-09 | 1917–1918 | 2 | |
| Italy | Italy | Italy, Italy | 1918-01- | -- | 1918–1986 | 15 | |
| Imperial Theatre | Imperial Theatre | United States of America, New York, 249 W 45th St | 1924-05-01 | -- | 1924 | 1 | |
| Intimní scéna | Intimní scéna | Czech Republic, Tábor | 1924-12-18 | -- | 1924 | 1 | |
| Iðnó | Iðnó | Iceland, Reykjavík | 1932-11-24 | -- | 1932–1943 | 2 | |
| International House Theater | International House Theater | United States of America, Chicago | 1934-03-16 | 1934-03-17 | 1934 | 1 | |
| Ibsen Theatre | Ibsen Theatre | United States of America, New York | 1935-04-01 | -- | 1935 | 1 | |
| India | India | India | 1940-- | -- | 1940–2020 | 4 | |
| Irkutskij dramatičeskij teatr | Irkutskij dramatičeskij teatr (Irkutsk Drama Theatre) | Russia, Irkutsk | 1946-- | -- | 1946 | 1 | |
| Innsbruck | Innsbruck | Austria, Innsbruck | 1946-04-27 | 1946-04-28 | 1946 | 1 | |
| Independent Theatre | Independent Theatre | Australia, North Sydney, 271 Miller Street | 1946-10-10 | -- | 1946–1951 | 2 | |
| International Theatre | International Theatre | United States of America, New York | 1946-11-12 | 1947-02-19 | 1946 | 1 | |
| Intimiteatteri | Intimiteatteri | Finland, Helsinki | 1951-03-28 | -- | 1951–1962 | 3 | |
| Ithaca College Little Theatre | Ithaca College Little Theatre | United States of America, Ithaca, Ithaca College | 1952-02-28 | 1952-03-01 | 1952 | 1 | |
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