| Independent Theatre | Independent Theatre | Australia, North Sydney, 271 Miller Street | 1946-10-10 | -- | 1946–1951 | 2 | |
| Innsbruck | Innsbruck | Austria, Innsbruck | 1946-04-27 | 1946-04-28 | 1946 | 1 | |
| Innsbrucker Kellertheater | Innsbrucker Kellertheater | Austria, Innsbruck, Adolf-Pichler-Platz 8 | 2004-10-20 | 2004-11-30 | 2004 | 1 | |
| Instituto LING | Instituto LING | Brazil, Porto Alegre, R. João Caetano, 440 | 2018-05-17 | 2018-05-26 | 2018 | 1 | |
| Inner Stage, The, University of Guelph | The Inner Stage, University of Guelph | Canada, Guelph, 50 Stone Road East | 1990-11-25 | 1990-12-01 | 1990 | 1 | |
| Irving Greenberg Theatre Centre | Irving Greenberg Theatre Centre | Canada, Ottawa, 1233 Wellington Street West | 2009-03-10 | 2009-03-21 | 2009 | 1 | |
| Imperial Theatre | Imperial Theatre | Canada, Vancouver | 1908-07-09 | 1908-07-09 | 1908 | 1 | |
| Iberoamericano de Teatro de Bogotá | Iberoamericano de Teatro de Bogotá | Colombia, Bogotá, Cundinamarca, Carrera 19 # 37-53 | 2008-03-07 | 2008-03-10 | 2008 | 1 | |
| Interimstheater Brünn | Interimstheater Brünn | Czech Republic, Brno, Žerotín square | 1880-01-01 | -- | 1880 | 1 | |
| Intimní scéna | Intimní scéna | Czech Republic, Tábor | 1924-12-18 | -- | 1924 | 1 | |
| Ishøj Centersal | Ishøj Centersal | Denmark, Ishøj | 2002-11-15 | -- | 2002–2004 | 2 | |
| Ismailia Culture Palace Theatre | Ismailia Culture Palace Theatre (قصر ثقافة الإسماعيلية) | Egypt, Ismaïlia | 2006-08-22 | -- | 2006 | 1 | |
| Ingatestone Hall | Ingatestone Hall | England, Essex, Hall Ln | 2007-09-21 | 2021-07-02 | 2007–2021 | 3 | |
| Incognito Theatre | Incognito Theatre | England, Friern Barnet, London, Holly Park Road | 2005-02-08 | 2012-12-01 | 2005–2012 | 2 | |
| Ipswich | Ipswich | England, Ipswich | -- | -- | | | |
| Islington | Islington | England, London | -- | -- | | | |
| Institute of Contemporary Arts (ICA) | Institute of Contemporary Arts (ICA) | England, London, The Mall | 1995-07-04 | 1995-07-08 | 1995 | 1 | |
| Imperial Theatre | Imperial Theatre | England, Westminster, London, Tothill Street | 1903-01-25 | 1903-01-26 | 1903 | 2 | |
| Ida Aalbergin kiertue | Ida Aalbergin kiertue | Finland | 1903-- | -- | 1903–1908 | 7 | |
| Intimiteatteri | Intimiteatteri | Finland, Helsinki | 1951-03-28 | -- | 1951–1962 | 3 | |
| Iitti | Iitti | Finland, Iitti | -- | -- | | | |
| Institut Méditerranéen des Métiers du Spectacle - IMMS | Institut Méditerranéen des Métiers du Spectacle - IMMS | France, Marseille, 41 rue Jobin | 2017-04-11 | 2017-04-15 | 2017 | 1 | |
| Île-Saint-Louis-Paul Rey, Théâtre de l' | Théâtre de l'Île-Saint-Louis-Paul Rey | France, Paris, 39 quai d'Anjou | 2009-04-21 | 2009-05-24 | 2009 | 1 | |
| Ingeborg-Drewitz-Bibliothek | Ingeborg-Drewitz-Bibliothek | Germany | 2023-08-31 | 2023-08-31 | 2023 | 1 | |
| IGS Garbsen | IGS Garbsen | Germany, Garbsen, Meyenfelder Str. 8, | 2010-10-30 | -- | 2010 | 1 | |
| Immenstadt | Immenstadt | Germany, Immenstadt | -- | -- | | | |
| Itzehoe | Itzehoe | Germany, Itzehoe | 2002-09-26 | -- | 2002 | 1 | |
| International Festival of Monodrama - Die Pumpe | International Festival of Monodrama - Die Pumpe | Germany, Kiel | 2006-11-11 | -- | 2006 | 1 | |
| Intimes Theater | Intimes Theater | Germany, Nürnberg, Wolfsschlucht | 1901-01-03 | -- | 1901–1912 | 7 | |
| Iðnó | Iðnó | Iceland, Reykjavík | 1932-11-24 | -- | 1932–1943 | 2 | |
| India | India | India | 1940-- | -- | 1940–2020 | 4 | |
| Iran | Iran | Iran, Iran | 1993-02-03 | -- | 1993–2017 | 3 | |
| International Theatre of Tehran | International Theatre of Tehran | Iran, Tehran | 1970-- | -- | 1970 | 1 | |
| Iranshahr | Iranshahr | Iran, Tehran, Artists' Park, Iranshahr St. | 2020-02-16 | 2020-03-16 | 2020 | 1 | |
| 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 | |
| Ireland | Ireland | Ireland | 1980-01-29 | 1980-04-19 | 1980 | 1 | |
| Iontas Theatre | Iontas Theatre | Ireland, Castleblayney Co, Monaghan, Conabury | 2007-03-09 | -- | 2007 | 1 | |
| Irish Theatre, The | The Irish Theatre | Ireland, Dublin | 1917-04-23 | 1918-02-09 | 1917–1918 | 2 | |
| Il Torrione | Il Torrione | Italy, Città di Castello, via Gramsci 28 | 2011-06-23 | -- | 2011 | 1 | |
| Italy | Italy | Italy, Italy | 1918-01- | -- | 1918–1986 | 16 | |
| Il Piccolo Teatro Instabile | Il Piccolo Teatro Instabile | Italy, Turin, via Garessio 18 | 2004-04-24 | -- | 2004 | 1 | |
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