| MGA Productions Limited | MGA Productions Limited | 1939 | 1 | |
| Maryland State Arts Council | Maryland State Arts Council | 2021 | 1 | |
| Maxim Gorki Theater | Maxim Gorki Theater | 1967 – 2021 | 15 | |
| Meßthaler-Ensemble vom Neuen Deutschen Theater München, Das | Das Meßthaler-Ensemble vom Neuen Deutschen Theater München | 1895 | 1 | |
| Mario Michelli | Mario Michelli | 2010 | 1 | |
| Meininger Hofkapelle | Meininger Hofkapelle (Meiningen Court Orchestra) | 2024 | 1 | |
| Mockingbird Theatre | Mockingbird Theatre | 2000 | 1 | |
| Makhdoomi's Group | Makhdoomi's Group | 2006 | 1 | |
| Mezinárodní festival Divadlo | Mezinárodní festival Divadlo | 2007 | 1 | |
| Ministério da Cultura | Ministério da Cultura | 2020 | 2 | |
| Manhattan Company | Manhattan Company | 1904 – 1910 | 17 | |
| Montgomery Theatre, The | The Montgomery Theatre | 2011 | 2 | |
| Maurice Campbell's Company | Maurice Campbell's Company | 1905 | 3 | |
| Malmö City Theatre | Malmö City Theatre | 1951 | 1 | |
| Münchner Kammerspiele (Schauspielhaus) | Münchner Kammerspiele (Schauspielhaus) | 1989 – 2023 | 10 | |
| Melbourne City Council | Melbourne City Council | 1970 – 1980 | 3 | |
| Moskovskij Hudožestvennyj akademičeskij teatr | Moskovskij Hudožestvennyj akademičeskij teatr (Moscow Art Theatre) | 1900 – 1924 | 7 | |
| Masquers | Masquers | 2003 | 1 | |
| Magadan State Musical and Drama Theatre | Magadan State Musical and Drama Theatre | 2024 – 2025 | 1 | |
| Městské divadlo v Táboře | Městské divadlo v Táboře | 1924 | 1 | |
| Münchener Dramatische Gesellschaft | Münchener Dramatische Gesellschaft | 1900 | 2 | |
| Metropolitan Players, The | The Metropolitan Players | 1912 – 1913 | 3 | |
| Marco Maltauro's Ensemle | Marco Maltauro's Ensemle | 1994 | 1 | |
| Ministero della cultura (MiBACT) | Ministero della cultura (MiBACT) | 2024 – 2025 | 3 | |
| Móricz Zsigmond Színház | Móricz Zsigmond Színház | 1995 | 2 | |
| Melbourne Festival | Melbourne Festival | 2011 – 2012 | 2 | |
| Melafestivalen | Melafestivalen | 2012 | 1 | |
| MIDI LIDI | MIDI LIDI | 2011 – 2012 | 3 | |
| Museo Deseo | Museo Deseo | 2006 | 1 | |
| Musica Independent Theatre Group, La | La Musica Independent Theatre Group | 2009 – 2013 | 17 | |
| Mariinsky Theatre Chorus | Mariinsky Theatre Chorus | 2005 | 1 | |
| Monologtheater | Monologtheater | 2023 | 2 | |
| Melbourne Theatre Company | Melbourne Theatre Company | 1970 – 1998 | 15 | |
| Mecklenburgisches Staatstheater Schwerin | Mecklenburgisches Staatstheater Schwerin | 1994 – 2005 | 4 | |
| Moskva Kunstnerteater | Moskva Kunstnerteater | 1905 | 3 | |
| Montreal Stage Society | Montreal Stage Society | 1918 | 1 | |
| Munroe Park Theater Guild, The | The Munroe Park Theater Guild | 2001 | 1 | |
| Melbourne Fringe Festival | Melbourne Fringe Festival | 2011 | 1 | |
| Mary Shaw Company | Mary Shaw Company | 1903 | 3 | |
| Meadow Brook Theatre | Meadow Brook Theatre | 1972 | 1 | |
| milwaukee chamber theatre | Milwaukee Chamber Theatre | 2025 | 1 | |
| Mingei (People's Theatre) | Mingei (People's Theatre) | 1953 – 2002 | 6 | |
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