| Incognito Theatre | Incognito Theatre | England, Friern Barnet, London, Holly Park Road | 2005-02-08 | 2012-12-01 | 2005–2012 | 2 | |
| 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 | |
| Imperial Theatre | Imperial Theatre | United States of America, Saint-Louis | 1904-11-17 | 1904-11-17 | 1904 | 1 | |
| Italy | Italy | Italy, Italy | 1918-01- | 1980-03-24 | 1918–2021 | 19 | |
| Instituto LING | Instituto LING | Brazil, Porto Alegre, R. João Caetano, 440 | 2018-05-17 | 2018-05-26 | 2018 | 1 | |
| 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 | |
| Ingeborg-Drewitz-Bibliothek | Ingeborg-Drewitz-Bibliothek | Germany | 2023-08-31 | 2023-08-31 | 2023 | 1 | |
| Iaşi | Iaşi | Romania, Iaşi | -- | -- | | | |
| Iacobeni | Iacobeni | Romania, Iacobeni | -- | -- | | | |
| Idrettshallen | Idrettshallen | Norway, Sogndal, Lunnamyri 4 | 1971-10-22 | 1997-10-13 | 1971–1997 | 2 | |
| Innsbrucker Kellertheater | Innsbrucker Kellertheater | Austria, Innsbruck, Adolf-Pichler-Platz 8 | 2004-10-20 | 2004-11-30 | 2004 | 1 | |
| Iontas Theatre | Iontas Theatre | Ireland, Castleblayney Co, Monaghan, Conabury | 2007-03-09 | -- | 2007 | 1 | |
| International House Theater | International House Theater | United States of America, Chicago | 1934-03-16 | 1934-03-17 | 1934 | 1 | |
| Ingebrigt Davik-huset | Ingebrigt Davik-huset | Norway, Brattvåg, Bernt Hildrevegen 2 | 2011-04-28 | 2014-04-01 | 2011–2014 | 2 | |
| Iranshahr | Iranshahr | Iran, Tehran, Artists' Park, Iranshahr St. | 2020-02-16 | 2020-03-16 | 2020 | 1 | |
| Ismailia Culture Palace Theatre | Ismailia Culture Palace Theatre (قصر ثقافة الإسماعيلية) | Egypt, Ismaïlia | 2006-08-22 | -- | 2006 | 1 | |
| Ibsen Theatre | Ibsen Theatre | United States of America, New York | 1935-04-01 | -- | 1935 | 1 | |
| Ingensteds | Ingensteds | Norway, Oslo, Brenneriveien 9 | 2014-12-14 | -- | 2014 | 1 | |
| Idrettshallen, Risør | Risør idrettshall | Norway, Risør | 1975-03-17 | -- | 1975 | 1 | |
| IOGT-huset | IOGT-huset | Norway, Bergen, Sverresgate 1 | 1990-02-08 | 1990-02-14 | 1990 | 1 | |
| IBSEN Museum & Teater | IBSEN Museum & Teater | Norway, Oslo, Henrik Ibsens gate 26 | 2022-03-20 | 2022-06-12 | 2022 | 2 | |
| İş Sanat Kültür Merkezi | İş Sanat Kültür Merkezi | Turkey, Levent/İstanbul, İş Kuleleri, Büyükdere Cd., | 2010-02-28 | 2010-05-16 | 2010 | 1 | |
| Ibsenhuset | Ibsenhuset | Norway, Skien, Lundegata 6 | 1973-09-07 | 2024-04-25 | 1973–2024 | 39 | |
| Inderøy Kulturhus | Inderøy Kulturhus | Norway, Sakshaug | 1993-03-11 | -- | 1993 | 1 | |
| Il Torrione | Il Torrione | Italy, Città di Castello, via Gramsci 28 | 2011-06-23 | -- | 2011 | 1 | |
| Ishøj Centersal | Ishøj Centersal | Denmark, Ishøj | 2002-11-15 | -- | 2002–2004 | 2 | |
| Ianca | Ianca | Romania, Ianca | -- | -- | | | |
| Ibsenmuseet | Ibsenmuseet | Norway, Oslo, Henrik Ibsens gate 26 | 2002-10-02 | 2003-10-26 | 2002–2012 | 6 | |
| IATC Studio Cassandra | IATC Studio Cassandra | Romania, Bucharest, Str. Matei Voievod nr. 75-77 | 1957-03-15 | -- | 1957–1985 | 4 | |
| Interzona | Interzona | Italy, Verona, Via Santa Teresa, 6 | 1999-10-07 | -- | 1999 | 1 | |
| Ida Aalbergin kiertue | Ida Aalbergin kiertue | Finland | 1903-- | -- | 1903–1908 | 7 | |
| Innsjön | Innsjön | Sweden, Innsjön | 1911-07-03 | 1911-07-04 | 1911 | 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 | |
| Interimstheater Brünn | Interimstheater Brünn | Czech Republic, Brno, Žerotín square | 1880-01-01 | -- | 1880 | 1 | |
| Iran | Iran | Iran, Iran | 1993-02-03 | -- | 1993–2017 | 3 | |
| International Theatre of Tehran | International Theatre of Tehran | Iran, Tehran | 1970-- | -- | 1970 | 1 | |
| Ingatestone Hall | Ingatestone Hall | England, Essex, Hall Ln | 2007-09-21 | 2021-07-02 | 2007–2021 | 3 | |
| Imperial Theatre | Imperial Theatre | United States of America, New York, 249 W 45th St | 1924-05-01 | -- | 1924 | 1 | |
| Irazee | Irazee | United States of America, Irazee | -- | -- | | | |
| Instituto Português do Desporto e da Juventude | Instituto Português do Desporto e da Juventude | Portugal, Lisbon | 2023-06-05 | 2023-06-05 | 2023 | 1 | |
| Istropolitana MDPOH | Istropolitana MDPOH | Slovak Republic, Bratislava, Ventúrska 3 | 2012-06-26 | -- | 2012 | 1 | |
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