| Izmir | Izmir | Turkey, Izmir | 1903-11- | 2013-05- | 1903–2012 | 2 | |
| Izmail | Izmail | Ukraine, Izmail | -- | -- | | | |
| Izabella Cywińska Nowy Theatre | Izabella Cywińska Nowy Theatre (Izabella Cywińska New Theatre) | Poland, Poznań, Dąbrowskiego 5 | 1967-05-12 | 2025-05-22 | 1967–2025 | 6 | |
| Ivano-Frankivsk | Ivano-Frankivsk | Ukraine, Ivano-Frankivsk | 1907-03- | 1907-04- | 1907 | 1 | |
| Itzehoe | Itzehoe | Germany, Itzehoe | 2002-09-26 | -- | 2002 | 1 | |
| Ithaca College Little Theatre | Ithaca College Little Theatre | United States of America, Ithaca, Ithaca College | 1952-02-28 | 1952-03-01 | 1952 | 1 | |
| Itaú Cultural | Itaú Cultural | Brazil, São Paulo, Avenida Paulista, 149 - Bela Vista, São Paulo - State of São Paulo, Brazil | 2022-09-29 | 2022-10-01 | 2022 | 1 | |
| Italy | Italy | Italy, Italy | 1918-01- | 1980-03-24 | 1918–2021 | 19 | |
| ITA ensemble | ITA ensemble | Netherlands, Amsterdam, Leidseplein 26 | 2021-11-05 | 2021-11-13 | 2021 | 1 | |
| Istropolitana MDPOH | Istropolitana MDPOH | Slovak Republic, Bratislava, Ventúrska 3 | 2012-06-26 | -- | 2012 | 1 | |
| Istindportalen | Istindportalen | Norway, Heggelia, Kapellveien 2 | 2007-03-12 | -- | 2007 | 1 | |
| Isthmus Playhouse. Madison Civic Center | Isthmus Playhouse. Madison Civic Center | United States of America, Madison, 201 State Street | 1999-10-22 | 1999-11-14 | 1999 | 1 | |
| Istanbul | Istanbul | Turkey, Istanbul | 1900-12- | 2014-05-29 | 1900–2014 | 5 | |
| Ismailia Culture Palace Theatre | Ismailia Culture Palace Theatre (قصر ثقافة الإسماعيلية) | Egypt, Ismaïlia | 2006-08-22 | -- | 2006 | 1 | |
| Islington | Islington | England, London | -- | -- | | | |
| Island Arts Centre | Island Arts Centre | Northern Ireland, Lisburn, Lagan Valley Island | 2011-04-11 | -- | 2011–2018 | 2 | |
| Islamabad | Islamabad | Pakistan, Islamabad | 2006-05-17 | -- | 2006 | 1 | |
| Ishøj Centersal | Ishøj Centersal | Denmark, Ishøj | 2002-11-15 | -- | 2002–2004 | 2 | |
| Isbjørnhallen | Isbjørnhallen | Norway, Hammerfest, Meridiangata 8 | 1997-11-05 | 1997-11-06 | 1997 | 1 | |
| Isala Theater | Isala Theater | Netherlands, Capelle aan Den IJssel, Stadsplein 5 | 2009-12-22 | -- | 2009–2013 | 2 | |
| İş Sanat Kültür Merkezi | İş Sanat Kültür Merkezi | Turkey, Levent/İstanbul, İş Kuleleri, Büyükdere Cd., | 2010-02-28 | 2010-05-16 | 2010 | 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 | |
| Irving Greenberg Theatre Centre | Irving Greenberg Theatre Centre | Canada, Ottawa, 1233 Wellington Street West | 2009-03-10 | 2009-03-21 | 2009 | 1 | |
| Ironwood Opera House | Ironwood Opera House | United States of America, Ironwood | 1899-02-24 | 1899-02-24 | 1899 | 1 | |
| Irondale Center | Irondale Center | United States of America, Brooklyn, 85 South Oxford Street | 2022-10-05 | 2022-11-20 | 2022 | 1 | |
| Irkutskij dramatičeskij teatr | Irkutskij dramatičeskij teatr (Irkutsk Drama Theatre) | Russia, Irkutsk | 1946-- | -- | 1946 | 1 | |
| Irish Theatre, The | The Irish Theatre | Ireland, Dublin | 1917-04-23 | 1918-02-09 | 1917–1918 | 2 | |
| Irish Cultural Center | Irish Cultural Center () | United States of America, Phoenix, North Central Avenue, 1106, Central City | 2025-07-31 | 2025-08-03 | 2025 | 1 | |
| Ireland | Ireland | Ireland | 1980-01-29 | 1980-04-19 | 1980 | 1 | |
| Irazee | Irazee | United States of America, Irazee | -- | -- | | | |
| Iranshahr Theatre | Iranshahr Theatre | Iran, Tehran | 2020-02-16 | 2025-01-21 | 2020–2024 | 2 | |
| Iranian Artists Forum, Entezami Hall | Iranian Artists Forum, Entezami Hall | Iran, Tehran, Iranshahr Street, Boostan Honarmandan | 2018-02-23 | 2023-07-11 | 2018–2023 | 2 | |
| Iran Tamasha Venue | Iran Tamasha Venue | Iran, Tehran, No 3, Semnan St., Nejat Elahi St., Ferdowsi square, Enghelab St | 2018-12-28 | -- | 2018 | 1 | |
| Iran | Iran | Iran, Iran | 1993-02-03 | -- | 1993–2017 | 3 | |
| Ipswich | Ipswich | England, Ipswich | -- | -- | | | |
| Iowa City Community Theatre | Iowa City Community Theatre | United States of America, Iowa City, 4261 Oak Crest Hill Rd SE | 2005-03-04 | 2005-03-20 | 2005 | 1 | |
| Iontas Theatre | Iontas Theatre | Ireland, Castleblayney Co, Monaghan, Conabury | 2007-03-09 | -- | 2007 | 1 | |
| Ion Luca Caragiale National Theatre | Ion Luca Caragiale National Theatre | Romania, Bucharest, Bulevardul Nicolae Bălcescu 2, București 040242, Romania | 2024-09-19 | 2024-10-11 | 2024 | 1 | |
| Ion Caramitru Hall | Ion Caramitru Hall | Romania, Bucharest | -- | -- | | | |
| IOGT-huset | IOGT-huset | Norway, Bergen, Sverresgate 1 | 1990-02-08 | 1990-02-14 | 1990 | 1 | |
| Intimní scéna | Intimní scéna | Czech Republic, Tábor | 1924-12-18 | -- | 1924 | 1 | |
| Intimiteatteri | Intimiteatteri | Finland, Helsinki, Ratakatu 9 | 1951-03-28 | -- | 1951–1962 | 3 | |
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