| Interzona | Interzona | Italy, Verona, Via Santa Teresa, 6 | 1999-10-07 | -- | 1999 | 1 | |
| Idrettshallen på Tråstad skole | Idrettshallen på Tråstad skole | Norway, Kongsvinger | 1971-09-29 | 1971-09-29 | 1971 | 1 | |
| Innsjön | Innsjön | Sweden, Innsjön | 1911-07-03 | 1911-07-04 | 1911 | 1 | |
| IBSEN Museum & Teater | IBSEN Museum & Teater | Norway, Oslo, Henrik Ibsens gate 26 | 2022-03-20 | 2022-05-20 | 2022 | 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 | |
| Iran | Iran | Iran, Iran | 1993-02-03 | -- | 1993–2017 | 3 | |
| Instituto LING | Instituto LING | Brazil, Porto Alegre, R. João Caetano, 440 | 2018-05-17 | 2018-05-26 | 2018 | 1 | |
| Ingatestone Hall | Ingatestone Hall | England, Essex, Hall Ln | 2007-09-21 | 2021-07-02 | 2007–2021 | 3 | |
| Izmail | Izmail | Ukraine, Izmail | -- | -- | | | |
| Imperial Theatre | Imperial Theatre | United States, New York, 249 W 45th St | 1924-05-01 | -- | 1924 | 1 | |
| Irazee | Irazee | United States, Irazee | -- | -- | | | |
| Illnau-Effretikon ZH | Illnau-Effretikon ZH | Switzerland | 2002-11-16 | -- | 2002 | 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 | |
| Isbjørnhallen | Isbjørnhallen | Norway, Hammerfest, Meridiangata 8 | 1997-11-05 | 1997-11-06 | 1997 | 1 | |
| Istindportalen | Istindportalen | Norway, Heggelia, Kapellveien 2 | 2007-03-12 | -- | 2007 | 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 | |
| Iowa City Community Theatre | Iowa City Community Theatre | United States, Iowa City, 4261 Oak Crest Hill Rd SE | 2005-03-04 | 2005-03-20 | 2005 | 1 | |
| India Habitat Centre | India Habitat Centre | India, New Delhi, 94, Lodhi Road | 2017-02-19 | 2017-02-19 | 2017 | 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 | |
| Ingensteds | Ingensteds | Norway, Oslo, Brenneriveien 9 | 2014-12-14 | -- | 2014 | 1 | |
| Ibestad Samfunnshus | Ibestad Samfunnshus | Norway, Hamnvik, 9450 Hamnvik | 1970-02-28 | -- | 1970 | 1 | |
| Inkonst | Inkonst | Sweden, Malmö, Bergsgatan 29 | 2006-09-29 | 2006-10-01 | 2006 | 1 | |
| IGS Garbsen | IGS Garbsen | Germany, Garbsen, Meyenfelder Str. 8, | 2010-10-30 | -- | 2010 | 1 | |
| Immenstadt | Immenstadt | Germany, Immenstadt | -- | -- | | | |
| Islington | Islington | England, London | -- | -- | | | |
| Idavoll | Idavoll | Norway, Ørsta | 1961-01-26 | -- | 1961–1963 | 2 | |
| Ivano-Frankivsk | Ivano-Frankivsk | Ukraine, Ivano-Frankivsk | 1907-03- | 1907-04- | 1907 | 1 | |
| Iran Tamasha Venue | Iran Tamasha Venue | Iran, Tehran, No 3, Semnan St., Nejat Elahi St., Ferdowsi square, Enghelab St | 2018-12-28 | -- | 2018 | 1 | |
| Indiana Repertory Theatre | Indiana Repertory Theatre | United States, Indianapolis, 140 W. Washington Street | 2001-01-09 | 2001-02-03 | 2001 | 1 | |
| Idavollen | Idavollen | Norway, Ørstavik | 1952-02-29 | -- | 1952–1956 | 3 | |
| Ibsengården | Ibsengården | Norway, Skien, Snipetorp | 2001-08-23 | 2004-08-26 | 2001–2004 | 2 | |
| Intimní scéna | Intimní scéna | Czech Republic, Tábor | 1924-12-18 | -- | 1924 | 1 | |
| Ida Aalbergin kiertue | Ida Aalbergin kiertue | Finland | 1903-- | -- | 1903–1908 | 7 | |
| Intima Teatern | Intima Teatern | Sweden, Stockholm, Barnhusgatan 20 | 1912-11-01 | 1919-03-14 | 1912–1919 | 3 | |
| Institut Papa Gueye Fall | Institut Papa Gueye Fall | Senegal, Dakar | 2021-05-19 | -- | 2021 | 1 | |
| International Festival of Monodrama | International Festival of Monodrama | Ukraine, Kiev | 2006-09-23 | -- | 2006 | 1 | |
| Imperial Theatre | Imperial Theatre | United States, Saint-Louis | 1904-11-17 | 1904-11-17 | 1904 | 1 | |
| Istanbul | Istanbul | Turkey, Istanbul | 1900-12- | 2014-05-29 | 1900–2014 | 5 | |
| International Theatre of Tehran | International Theatre of Tehran | Iran, Tehran | 1970-- | -- | 1970 | 1 | |
| Impossible Ragtime Theater | Impossible Ragtime Theater | United States, New York | 1979-01-28 | -- | 1979 | 1 | |
| Iaşi | Iaşi | Romania, Iaşi | -- | -- | | | |
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