| Little Theatre of New Haven, The | The Little Theatre of New Haven | 1931 | 1 | |
| Live Theatre Workshop | Live Theatre Workshop | 2025 | 1 | |
| Livros Cotovia | Livros Cotovia | 2020 | 2 | |
| Loft Theatre Company, The | The Loft Theatre Company | 2007 – 2018 | 2 | |
| London Haymarket Theatre Company | London Haymarket Theatre Company | 1895 | 3 | |
| Lorentz Lundgrens sällskap | Lorentz Lundgrens sällskap | 1885 – 1887 | 4 | |
| Lotten Dorschs sällskap | Lotten Dorschs sällskap | 1892 | 2 | |
| Louisiana Players' Guild | Louisiana Players' Guild | 1937 | 1 | |
| Luzége Festival Company | Luzége Festival Company | 2023 | 9 | |
| Lwowski Teatr Ludowy | Lwowski Teatr Ludowy | 1912 | 1 | |
| Lydia Yavorskas (princess Bariatinsky) Matinees | Lydia Yavorskas (princess Bariatinsky) Matinees | 1909 – 1911 | 2 | |
| Lynchburg College Theatre | Lynchburg College Theatre | 2005 | 1 | |
| Lynet | Lynet | 2010 | 2 | |
| Lyric Hammersmith Theatre, The | The Lyric Hammersmith Theatre | 1994 – 2025 | 5 | 1 |
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