| Lingeman Design / Build | Lingeman Design / Build | — | (415) 606 9619 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Linscott Engineering Contractors INC | Kathryn Royer Linscott | — | (415) 492 1755 | Other | San Rafael · Marin County | — | — |
| Little John Construction | John Michael Waterhouse | john.ljc@gmail.com | (415) 726 9663 | GC, remodel, ADU | Novato · Marin County | — | — |
| Live Oak Fine Cabinetry & Millwork INC | Anthony Joseph Durkton | — | (415) 236 2456 | Other | San Rafael · Marin County | — | — |
| Living In Technology INC | Matthew Alexander Stachnik | matt@livingintechnology.com | (415) 990 7599 | Other | Novato · Marin County | — | — |
| Liza Guastucci DBA Guastucci Tree Service | Liza Marie Guastucci | — | (415) 456 4443 | Tree | Fairfax · Marin County | — | — |
| Llv Decorative Painting | Llv Decorative Painting | — | (415) 724 0302 | Windows, patio, painters | Mill Valley · Marin County | — | — |
| Lobl Construction | Oliver Francis Lobl | — | (415) 608 7662 | GC, remodel, ADU | Novato · Marin County | — | — |
| Local Low Voltage LLC | John Kurt Steddin | — | (415) 305 0169 | Other | San Rafael · Marin County | — | — |
| Local Plumbing | Fergal Sean Mc Mahon | info@localplumbingca.com | (415) 234-0370 | Other | San Rafael · Marin County | — | — |
| Loew Development Company | Loew Thomas | — | (415) 828 1240 | GC, remodel, ADU | Tiburon · Marin County | — | — |
| Logan Osborne Electric | Logan Bok Osborne | — | (415) 328 7058 | Electricians | Novato · Marin County | — | — |
| Lombardi Property Development LLC | Stephen Joseph Lombardi | — | (415) 609 8285 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| London Chimney Services INC | Mark Allen Rizzo | — | (415) 380 0330 | Other | Mill Valley · Marin County | — | — |
| London Tile | Gregory Michael Griffin | — | (415) 302 1489 | Other | Mill Valley · Marin County | — | — |
| Lonnie Haughton | Lonnie Haughton | — | (415) 388 8971 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Lookinland Custom Building LLC | Todd Lookinland | — | (415) 310 7927 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lopez Painting | Lopez Painting | — | (415) 342 0992 | Windows, patio, painters | San Rafael · Marin County | — | — |
| Lord Vering Contractors | Rodrick Harmon Lord | — | (818) 468 1558 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Lory Electric | Thomas Paul Lory | tl@loryelectric.com | (415) 758 0026 | Electricians | Novato · Marin County | — | — |
| Lost Boys Construction Corp | Alexander John Lykiardopoulos | — | (415) 488 5665 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Loumar Company | Marc Louis Mountanos | — | (415) 457 3361 | Other | Fairfax · Marin County | — | — |
| Lounsbury Built Luxury | Lounsbury Built Luxury | — | (415) 722 1793 | Electricians | San Rafael · Marin County | — | — |
| Lovelight Solutions LLC | Bret Michael Walburg | bret@lovelightsolutions.com | (415) 312 5262 | Electricians | San Anselmo · Marin County | — | — |
| Lovell Design And Build | John Clifton Lovell | — | (415) 378 8070 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Lowry Construction INC | Stephen Chesler Lowry | — | (415) 310 7201 | GC, remodel, ADU | Kentfield · Marin County | — | — |
| LP Construction Services | Lee Alan Perry | — | (415) 342 6402 | GC, remodel, ADU | San Anselmo · Marin County | — | — |
| Lucas Ryan Building | Lucas Ryan Building | — | (415) 786 5594 | GC, remodel, ADU | Novato · Marin County | — | — |
| Lucas Valley Designs | Lucas Valley Designs | — | (415) 225 8230 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lucio Landscape Construction,inc. | Sergio Alvarez | — | (415) 827 6421 | Windows, patio, painters | San Rafael · Marin County | — | — |
| Lucio Landscaping Services INC | Lucio Patricio Calderon Escobar | info@luciolandscape.com | (415) 717 9509 | Windows, patio, painters | San Rafael · Marin County | — | — |
| Luis Painting Company | Jose Luis Gonzalez Godinez | — | (415) 850 8091 | Windows, patio, painters | San Rafael · Marin County | — | — |
| Luis Vasquez | Luis Vasquez | — | (415) 302 0037 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lunny Grading & Paving INC | Kevin John Lunny | — | (415) 662 9800 | GC, remodel, ADU | Nicasio · Marin County | — | — |
| Lutz Electric | George Steven Lutz | — | (415) 806 0971 | Electricians | Novato · Marin County | — | — |
| M & M Builders | M & M Builders | — | (415) 717 0031 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| M 2 Design And Construction | Matthew Allan| Clark Matt Allan Clark | — | (415) 816 3403 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| M A Painting | M A Painting | — | (415) 342 3652 | Windows, patio, painters | Novato · Marin County | — | — |
| M A S Builders | M A S Builders | — | (415) 302 0123 | GC, remodel, ADU | Novato · Marin County | — | — |
| M C M Electric INC | Keith James Mc Mahon | — | (415) 608 4640 | Electricians | Novato · Marin County | — | — |