| Illinois Repertory Theatre University of Illinois | Illinois Repertory Theatre University of Illinois | 1988 | 1 | |
| Institutt for drama/film/teater | Institutt for drama/film/teater | 1994 | 1 | |
| Ibsen- og Hamsun-dagene 2009 | Ibsen- og Hamsun-dagene 2009 | 2009 | 1 | |
| Ibsen wo joensuru kai | Ibsen wo joensuru kai | 2006 – 2007 | 7 | |
| International Ibsen Festival for University Students | International Ibsen Festival for University Students | 2010 | 3 | |
| Ibseniana-festivalen | Ibseniana-festivalen | 1989 – 2004 | 24 | |
| Ibsen- og Hamsun-dagene 2007 | Ibsen- og Hamsun-dagene 2007 | 2007 | 1 | |
| International Ibsen Stage Festival | International Ibsen Stage (International Ibsen Stage Festival) | 2012 – 2013 | 16 | |
| Independent Theatre, The | The Independent Theatre | 1946 | 1 | |
| Incorporated Stage Society | Incorporated Stage Society | 1906 | 1 | |
| Ibsen- og Hamsun-dagene 2006 | Ibsen- og Hamsun-dagene 2006 | 2005 – 2006 | 2 | |
| Intimes Theater | Intimes Theater | 1909 | 1 | |
| Ibsen-museet i Grimstad | Ibsen-museet i Grimstad | 2006 – 2007 | 9 | |
| Ibsen- og Hamsun-dagene 2013 | Ibsen- og Hamsun-dagene 2013 | 2013 | 2 | |
| IPFW Department of Theatre | IPFW Department of Theatre | 2008 – 2014 | 2 | |
| Ibsen-Theater aus Berlin, Das | Das Ibsen-Theater aus Berlin | 1901 – 1912 | 60 | |
| Ibsenforbundet | Ibsenforbundet | 2004 – 2007 | 61 | |
| Ingun Bjørnsgaard Prosjekt | Ingun Bjørnsgaard Prosjekt | 2010 – 2014 | 5 | |
| International Ibsen Festival 2010 | International Ibsen Festival 2010 | 2010 | 3 | |
| Ibsenfestivalen | Ibsenfestivalen (Ibsen Stage Festival) (Ibsenfestivalen) | 1990 – 2020 | 546 | 3 |
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