| Ibsenhuset | Ibsenhuset | Norway, Skien, Lundegata 6 | 1973-09-07 | 2024-04-25 | 1973–2024 | 39 | |
| Italy | Italy | Italy, Italy | 1918-01- | 1980-03-24 | 1918–2021 | 19 | |
| Intiman, Malmö Stadsteater | Intiman, Malmö Stadsteater | Sweden, Malmö, Östra Rönneholmsvägen 20 | 1954-10-08 | 2015-04-29 | 1954–2015 | 11 | |
| Irving Place Theatre | Irving Place Theatre | United States of America, New York, East 15th Street | 1897-04-12 | 1913-11-12 | 1897–1918 | 9 | |
| 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 | |
| Intimes Theater | Intimes Theater | Germany, Nürnberg, Wolfsschlucht | 1901-01-03 | -- | 1901–1912 | 7 | |
| Ibsenmuseet | Ibsenmuseet | Norway, Oslo, Henrik Ibsens gate 26 | 2002-10-02 | 2003-10-26 | 2002–2012 | 6 | |
| Istanbul | Istanbul | Turkey, Istanbul | 1900-12- | 2014-05-29 | 1900–2014 | 5 | |
| India | India | India | 1940-- | -- | 1940–2020 | 4 | |
| IATC Studio Cassandra | IATC Studio Cassandra | Romania, Bucharest, Str. Matei Voievod nr. 75-77 | 1957-03-15 | -- | 1957–1985 | 4 | |
| Intiman Theatre | Intiman Theatre | United States of America, Seattle, 201 Mercer Street | 1996-12-08 | 2012-08-25 | 1996–2012 | 4 | |
| Idavollen | Idavollen | Norway, Ørstavik | 1952-02-29 | -- | 1952–1956 | 3 | |
| Iran | Iran | Iran, Iran | 1993-02-03 | -- | 1993–2017 | 3 | |
| Ingatestone Hall | Ingatestone Hall | England, Essex, Hall Ln | 2007-09-21 | 2021-07-02 | 2007–2021 | 3 | |
| Intimiteatteri | Intimiteatteri | Finland, Helsinki, Ratakatu 9 | 1951-03-28 | -- | 1951–1962 | 3 | |
| Intima Teatern | Intima Teatern | Sweden, Stockholm, Barnhusgatan 20 | 1912-11-01 | 1919-03-14 | 1912–1919 | 3 | |
| Idrettshuset | Idrettshuset | Norway, Straumsnes | 1956-02-08 | -- | 1956–1963 | 3 | |
| Ila fengsel | Ila fengsel | Norway, Eiksmarka, Jøssingveien 33 | 2012-11-28 | -- | 2012 | 2 | |
| Independent Theatre | Independent Theatre | Australia, North Sydney, 271 Miller Street | 1946-10-10 | -- | 1946–1951 | 2 | |
| Irish Theatre, The | The Irish Theatre | Ireland, Dublin | 1917-04-23 | 1918-02-09 | 1917–1918 | 2 | |
| Incognito Theatre | Incognito Theatre | England, Friern Barnet, London, Holly Park Road | 2005-02-08 | 2012-12-01 | 2005–2012 | 2 | |
| Idavoll | Idavoll | Norway, Ørsta | 1961-01-26 | -- | 1961–1963 | 2 | |
| Imperial Theatre | Imperial Theatre | England, Westminster, London, Tothill Street | 1903-01-25 | 1903-01-26 | 1903 | 2 | |
| Industrial space | Industrial Space | United States of America, New York, Chelsea | 1994-08- | 1995-11- | 1994 | 2 | |
| Idrettshallen | Idrettshallen | Norway, Sogndal, Lunnamyri 4 | 1971-10-22 | 1997-10-13 | 1971–1997 | 2 | |
| Ingebrigt Davik-huset | Ingebrigt Davik-huset | Norway, Brattvåg, Bernt Hildrevegen 2 | 2011-04-28 | 2014-04-01 | 2011–2014 | 2 | |
| Ishøj Centersal | Ishøj Centersal | Denmark, Ishøj | 2002-11-15 | -- | 2002–2004 | 2 | |
| IBSEN Museum & Teater | IBSEN Museum & Teater | Norway, Oslo, Henrik Ibsens gate 26 | 2022-03-20 | 2022-06-12 | 2022 | 2 | |
| Ibsengården | Ibsengården | Norway, Skien, Snipetorp | 2001-08-23 | 2004-08-26 | 2001–2004 | 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 | |
| Island Arts Centre | Island Arts Centre | Northern Ireland, Lisburn, Lagan Valley Island | 2011-04-11 | -- | 2011–2018 | 2 | |
| Illinois Theatre | Illinois Theatre | United States of America, Chicago, 65 E. Jackson Boulevard | 1908-01-31 | -- | 1908–1927 | 2 | |
| Isala Theater | Isala Theater | Netherlands, Capelle aan Den IJssel, Stadsplein 5 | 2009-12-22 | -- | 2009–2013 | 2 | |
| Iðnó | Iðnó | Iceland, Reykjavík | 1932-11-24 | -- | 1932–1943 | 2 | |
| Izmir | Izmir | Turkey, Izmir | 1903-11- | 2013-05- | 1903–2012 | 2 | |
| Idrettsbygget | Idrettsbygget | Norway, Løkken Verk | 1969-09-17 | -- | 1969 | 2 | |
| IJmuiden Stadsschouwburg | IJmuiden Stadsschouwburg | Netherlands, Velsen, Stadsschouwburg Velsen | 2002-12-14 | -- | 2002–2003 | 2 | |
| Inderøy kulturhus | Inderøy kulturhus | Norway, Inderøy, Vennalivegen 15 | 2001-06-25 | -- | 2001–2006 | 2 | |
| Ireland | Ireland | Ireland | 1980-01-29 | 1980-04-19 | 1980 | 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 | |
| International Festival of Monodrama - Die Pumpe | International Festival of Monodrama - Die Pumpe | Germany, Kiel | 2006-11-11 | -- | 2006 | 1 | |
| Irving Greenberg Theatre Centre | Irving Greenberg Theatre Centre | Canada, Ottawa, 1233 Wellington Street West | 2009-03-10 | 2009-03-21 | 2009 | 1 | |
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