| Iaşi | Iaşi | Romania, Iaşi | -- | -- | | | |
| Iacobeni | Iacobeni | Romania, Iacobeni | -- | -- | | | |
| Ianca | Ianca | Romania, Ianca | -- | -- | | | |
| Irazee | Irazee | United States, Irazee | -- | -- | | | |
| Ineu | Ineu | Romania, Ineu | -- | -- | | | |
| Islington | Islington | England, London | -- | -- | | | |
| Immenstadt | Immenstadt | Germany, Immenstadt | -- | -- | | | |
| Ileana | Ileana | Romania, Ileana | -- | -- | | | |
| Izmail | Izmail | Ukraine, Izmail | -- | -- | | | |
| Ipswich | Ipswich | England, Ipswich | -- | -- | | | |
| Iitti | Iitti | Finland, Iitti | -- | -- | | | |
| Indiana Repertory Theatre | Indiana Repertory Theatre | United States, Indianapolis, 140 W. Washington Street | 2001-01-09 | 2001-02-03 | 2001 | 1 | |
| Île, Théâtre de | Théâtre de l'Île | New Caledonia, Noumea, 161 Avenue James Cook | 2017-06-21 | 2017-06-25 | 2017 | 1 | |
| International Festival of Monodrama | International Festival of Monodrama | Ukraine, Kiev | 2006-09-23 | -- | 2006 | 1 | |
| Instituto Municipal de Educación | Instituto Municipal de Educación | Spain, Madrid, Calle de Mejía Lequerica, 21 | 1963-10-27 | -- | 1963 | 1 | |
| Imperial Theatre | Imperial Theatre | United States, Saint-Louis | 1904-11-17 | 1904-11-17 | 1904 | 1 | |
| International Theatre of Tehran | International Theatre of Tehran | Iran, Tehran | 1970-- | -- | 1970 | 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 | |
| Intimes Theater | Intimes Theater | Switzerland, Bern | 1909-10-21 | 1909-12-01 | 1909 | 1 | |
| Institute of Contemporary Arts (ICA) | Institute of Contemporary Arts (ICA) | England, London, The Mall | 1995-07-04 | 1995-07-08 | 1995 | 1 | |
| Innsbrucker Kellertheater | Innsbrucker Kellertheater | Austria, Innsbruck, Adolf-Pichler-Platz 8 | 2004-10-20 | 2004-11-30 | 2004 | 1 | |
| International House Theater | International House Theater | United States, Chicago | 1934-03-16 | 1934-03-17 | 1934 | 1 | |
| ITA ensemble | ITA ensemble | Netherlands, Amsterdam, Leidseplein 26 | 2021-11-05 | 2021-11-13 | 2021 | 1 | |
| Ibsenparken | Ibsenparken | Norway, Skien | 2006-05-23 | -- | 2006 | 1 | |
| Ismailia Culture Palace Theatre | Ismailia Culture Palace Theatre | Egypt, Ismaïlia | 2006-08-22 | -- | 2006 | 1 | |
| Isthmus Playhouse. Madison Civic Center | Isthmus Playhouse. Madison Civic Center | United States, Madison, 201 State Street | 1999-10-22 | 1999-11-14 | 1999 | 1 | |
| İş Sanat Kültür Merkezi | İş Sanat Kültür Merkezi | Turkey, Levent/İstanbul, İş Kuleleri, Büyükdere Cd., | 2010-02-28 | 2010-05-16 | 2010 | 1 | |
| Il Torrione | Il Torrione | Italy, Città di Castello, via Gramsci 28 | 2011-06-23 | -- | 2011 | 1 | |
| Instituto Andrés Soler (ANDA) | Instituto Andrés Soler (ANDA) | Mexico, Mexico City, Petén 45, Narvarte Poniente | 2000-10-14 | -- | 2000 | 1 | |
| Iontas Theatre | Iontas Theatre | Ireland, Castleblayney Co, Monaghan, Conabury | 2007-03-09 | -- | 2007 | 1 | |
| Irondale Center | Irondale Center | United States, Brooklyn, 85 South Oxford Street | 2022-10-05 | 2022-11-20 | 2022 | 1 | |
| Interimstheater Brünn | Interimstheater Brünn | Czech Republic, Brno, Žerotín square | 1880-01-01 | -- | 1880 | 1 | |
| Illinois Theatre | Illinois Theatre | United States, Rock Island | 1904-03-15 | 1904-03-15 | 1904 | 1 | |
| Ibsen Theatre | Ibsen Theatre | United States, New York | 1935-04-01 | -- | 1935 | 1 | |
| Idrettshallen, Risør | Risør idrettshall | Norway, Risør | 1975-03-17 | -- | 1975 | 1 | |
| Istropolitana MDPOH | Istropolitana MDPOH | Slovak Republic, Bratislava, Ventúrska 3 | 2012-06-26 | -- | 2012 | 1 | |
| IOGT-huset | IOGT-huset | Norway, Bergen, Sverresgate 1 | 1990-02-08 | 1990-02-14 | 1990 | 1 | |
| Inderøy Kulturhus | Inderøy Kulturhus | Norway, Sakshaug | 1993-03-11 | -- | 1993 | 1 | |
| Il Piccolo Teatro Instabile | Il Piccolo Teatro Instabile | Italy, Turin, via Garessio 18 | 2004-04-24 | -- | 2004 | 1 | |
| Ithaca College Little Theatre | Ithaca College Little Theatre | United States, Ithaca, Ithaca College | 1952-02-28 | 1952-03-01 | 1952 | 1 | |
| 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 | |
| Islamabad | Islamabad | Pakistan, Islamabad | 2006-05-17 | -- | 2006 | 1 | |
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