| Landworks Design / Build | Dean Andrew Wallace | — | (415) 269 0158 | Windows, patio, painters | Fairfax · Marin County | — | — |
| Landy Construction | Enriquez Horacio | — | (415) 786 3744 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Larkspur Building Company | Allen Christopher Bellis | — | (415) 847 6946 | GC, remodel, ADU | Larkspur · Marin County | — | — |
| Las Baulines Nursery INC | Zoe Blythe Gardiner | — | (415) 419 6022 | Windows, patio, painters | Stinson Beach · Marin County | — | — |
| Lasting Impression Design & Construction | Wojciech Jerzy Platek | — | (415) 235 9950 | GC, remodel, ADU | Novato · Marin County | — | — |
| Laura Kirwan Benson Electric INC | Richard Paul Benson | — | (415) 246 6616 | Electricians | Novato · Marin County | — | — |
| Laurence Daniel Brodkin | Laurence Daniel Brodkin | — | (415) 269 5848 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lawrence Schultz | Lawrence Schultz | — | (267) 241 6858 | Tree | San Rafael · Marin County | — | — |
| Layline Automation INC | Alexander Harrison Hvisc | — | (415) 758 0044 | Other | San Rafael · Marin County | — | — |
| Lazor Construction | James William Jr Lazor | — | (415) 637 2829 | GC, remodel, ADU | Kentfield · Marin County | — | — |
| Lcr Construction - Marin County | Lcr Construction - Marin County | — | (415) 240-5152 | GC, remodel, ADU | Sausalito · Marin County | — | — |
| Le Jardinier | Le Jardinier | — | (415) 385 3478 | Windows, patio, painters | Novato · Marin County | — | — |
| Lectric Larry | Lectric Larry | larry@lectriclarry.com | (415) 846 5779 | Electricians | Sausalito · Marin County | — | — |
| Lee Design & Build | Lee Design & Build | hannahy@leedesignbuild.com | (415) 499 8051 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lee Mechanical INC | Gary Byron Lee | — | (415) 883 4450 | Other | Novato · Marin County | — | — |
| Legacy Acoustic Interiors | Richard Patrick Smith | — | (415) 763 9215 | Other | Novato · Marin County | — | — |
| Legato Plumbing LLC | Artyom Davtyan | — | (415) 877 6655 | Other | Sausalito · Marin County | — | — |
| Leh Landscape | Leh Landscape | — | (415) 383 4047 | Tree | Mill Valley · Marin County | — | — |
| Lehmann Plumbing INC | Michelle Jeannette Lehmann | lehmannplumbing@ymail.com | (415) 499 0111 | HVAC | San Rafael · Marin County | — | — |
| Lehua Gardens INC | Honey Lehua Kearns | — | (415) 613 5042 | Windows, patio, painters | Mill Valley · Marin County | — | — |
| Leimer Construction | John Richard Leimer | admin@leimerconstruction.com | (415) 846 1176 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lemas Landscaping Corporation | Elmar Ramiro Mazariegos Gramajo | jonpinhorn.typedesign@gmail.com | (415) 879 7679 | Windows, patio, painters | San Rafael · Marin County | — | — |
| Leo's Glass Windows And Doors | Leo's Glass Windows And Doors | — | (415) 599 5155 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Leo's Tree Service | Vazquez Casas Leonel | — | (415) 819 5520 | Tree | San Rafael · Marin County | — | — |
| Leonardo Construction INC | Straccia Tiziano | — | (415) 425 0995 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Leoncio Espinoza-ordonez | Leoncio Espinoza-ordonez | — | (415) 419 4933 | Windows, patio, painters | San Rafael · Marin County | — | — |
| Levelform Landscaping | Zachary Davids Seibert | — | (415) 617 9461 | Windows, patio, painters | Mill Valley · Marin County | — | — |
| Levita Construction | Gabriel Antonio Estrada | — | (415) 867 6806 | GC, remodel, ADU | Novato · Marin County | — | — |
| Lewis Construction | Matthew Ernest Lewis | — | (415) 307 3889 | GC, remodel, ADU | Bolinas · Marin County | — | — |
| Lewis Construction | Michael Joseph Lewis | — | (415) 760 0475 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lex Electric | Lex Thomas Anderson | info@lex-electric.net | (415) 559 6545 | Electricians | San Rafael · Marin County | — | — |
| Lh Gao Construction INC | Liang Hong Gao | — | (415) 747 2688 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Light Wright | Light Wright | — | (415) 246 9535 | Electricians | Novato · Marin County | — | — |
| Lighthouse Construction Services INC | Charles Gerard Marden | — | (415) 389 1199 | GC, remodel, ADU | Mill Valley · Marin County | — | — |
| Lighthouse Electric | Paul Christopher Moran | — | (415) 710 6490 | Electricians | Mill Valley · Marin County | — | — |
| Lil Demo LLC | Richard Anthony Silva | 1833lildemo@gmail.com | (650) 240 6824 | Other | Kentfield · Marin County | — | — |
| Lima Construction And Tile INC | Kenneth Chapman Breuner | — | (415) 531 3505 | GC, remodel, ADU | San Rafael · Marin County | — | — |
| Lin Della Valle - General Contractor | Della Valle Lin General Contractor | — | (415) 272 0729 | GC, remodel, ADU | Kentfield · Marin County | — | — |
| Lindele Construction Company INC | Robert Nathan Johnson | — | (415) 681 3214 | Electricians | Novato · Marin County | — | — |
| Linehan Electric | Edward Francis Linehan | — | (415) 884 4424 | Electricians | Novato · Marin County | — | — |