| La-Decks | B | 2011 | Active |
| Labor Smart Inc | B | 2024 | Active |
| Lai's Lo - Temp Refrigeration Co Inc | B + C10, C20, C38 | 2013 | Active |
| Landa Builders Inc | B | 2025 | Active |
| Landline Construction Inc | B | 2021 | Active |
| Landmark Building, Inc | B | 2011 | Active |
| Landmark Construction Group Inc | B | 1997 | Active |
| Lannen Construction Inc | B | 2002 | Active |
| Lantana Development Company Inc | A, B + HAZ | 1999 | Active |
| Lar Development Inc | B | 2026 | Active |
| Lara Residential Construction Inc | B + C16, C36 | 2025 | Active |
| Lark Construction Services LLC | B | 2025 | Active |
| Lascheid Industries Inc | B + C33 | 2000 | Active |
| Lattanzi Construction Incorporated | B | 2000 | Active |
| Lavie's Construction Inc | B | 2016 | Active |
| Lax Integrated Express Solutions LLC | A | 2018 | Active |
| LCD Construction Inc | B | 2024 | Active |
| Lee L Development Co Inc | B | 1994 | Active |
| Lee's Roofing Corp | B + C39 | 2023 | Active |
| Legacy Builders La Inc | B | 2025 | Active |
| Legacy Innovative Construction Inc | B | 2023 | Active |
| Legacy Paving & Utilites Inc | A, B + C21 | 2025 | Active |
| Legion Builders Group | A, B + C15, C27, C36 +2 | 2019 | Active |
| Lehigh Construction Company | A, B + D06 | 1995 | Active |
| Leigh Construction Incorporated | B | 2000 | Active |
| Leilana Corporation | B | 2025 | Active |
| Leishman General Contractors | B | 1992 | Active |
| Lemco Construction Inc | B | 2019 | Active |
| Lena Construction Inc | B | 2021 | Active |
| Lensray Design Inc | B + C8 | 2013 | Active |
| Lepton Electric Incorporated | B + C10 | 2021 | Active |
| Let Jim Fix It | B | 2023 | Active |
| Letter Four Inc | B | 2017 | Active |
| Level Frame Construction Inc | B | 2021 | Active |
| Levelworks Construct & Renovate Inc | B | 2018 | Active |
| Leviticus Builders | B | 2026 | Active |
| LG Builders Group Inc | B | 2026 | Active |
| Lgo Construction | B | 2010 | Active |
| Liberty Builds | B + C8, C11, D39 +1 | 2021 | Active |
| Liberty Specialty | B + C8 | 2021 | Active |
| Lievc Inc | B | 2025 | Active |
| Lighthart Corporation The | A, B + C4, C10, C16 +5 | 1990 | Active |
| Lincoln Group Ca Corporation | B | 2023 | Active |
| Line Electric Inc | B + C10 | 2008 | Active |
| Lion Windows And Doors | B | 2012 | Active |
| Lions Construction Group Inc | B | 2023 | Active |
| Little Potato Inc | A, B | 2012 | Active |
| Livewell Builds LLC | B | 2025 | Active |
| Livingprospex Corporation | B | 2020 | Active |
| Livingston Built Inc | B | 2025 | Active |
| Llayee Construction Inc | B + C36 | 2017 | Active |
| LMR Home Improvement | B | 2025 | Active |
| Lo8 Construction Inc | B | 2024 | Active |
| Local Builds Inc | B | 2023 | Active |
| Local Roofers Builder Inc The | B + C39 | 2020 | Active |
| Lohi Construction Inc | B | 2022 | Active |
| Lomeli Construction | A, B | 2007 | Active |
| Lopez Gabriel Construction Inc | B | 2018 | Active |
| Lore's General Construction Inc | B | 2020 | Active |
| Los Angeles Conservation Corps Inc | B + C10, C27, C33 +2 | 2010 | Active |
| Los Angeles Construction Service Inc | B | 2026 | Active |
| Los Angeles Development Consultants Inc | A, B | 2020 | Active |
| Los Angeles Elite Construction LLC | B | 2026 | Active |
| Los Angeles Home Improvements | B | 2025 | Active |
| Los Angeles Remodeling & Development | B | 2021 | Active |
| Lotus Builders Inc | B | 2002 | Active |
| Lotus West Management Company Inc | B | 2026 | Active |
| Louis & Rose Construction Corp | B | 2021 | Active |
| Louis Construction Inc | B | 2009 | Active |
| Love Development Group | B | 2023 | Active |
| Love Home Renovations | B | 2019 | Active |
| Low Maintenance Inc | B | 2024 | Active |
| Lowe Enterprises Real Estate Group | B | 1995 | Active |
| LPG General Construction Corp | B | 2018 | Active |
| LSP Construction Inc | B | 2019 | Active |
| Lucio Inc | B | 2016 | Active |
| Luckett & Sons Construction Company | B + C36 | 1992 | Renew by Dec 31, 2026 |
| Lucky Air Construction Inc | B + C10, C20 | 2025 | Active |
| Ludi Construction Inc | B | 2022 | Active |
| Ludwig S C Construction LLC | B | 2014 | Active |
| Luma Development/Construction | B | 2026 | Active |
| Lumar Corporation | A, B | 2017 | Active |
| Lush Remodeling & Development Inc | B + D28 | 2015 | Active |
| Lush Remodeling Corporation | B | 2021 | Active |
| Lux Construction Group Inc | B | 2017 | Active |
| Lux General Contractor | B | 2024 | Active |
| M & D Contractors Inc | B + C20 | 2009 | Active |
| M & D Development & Construction Inc | B | 1997 | Active |
| M & M Electricians Co | B + C10 | 2012 | Active |
| M & M Electricians Co | B + C10 | 1997 | Active |
| M A C S Restoration Inc | B | 2026 | Active |
| M C S Builders Inc | B | 2006 | Active |
| M D M Builders Group | B | 2009 | Active |
| M Design House | B | 2013 | Active |
| M F B | B | 1986 | Active |
| M G Remodeling Inc | B | 2022 | Active |
| M H P Group LLC | B | 2023 | Active |
| M J M Builders Incorporated | B | 2002 | Active |
| M P M Painting Inc | B + C33 | 1991 | Renew by Dec 31, 2026 |
| M R Electrical Inc | B + C10 | 2019 | Active |