| Lewis Electric | James Bleekman Iii Lewis | — | (805) 235 3321 | Electricians | Point Arena · Mendocino County | — | — |
| Leyva Roofing | Uribe-leyva Gerardo | — | (707) 391 0842 | Other roofers | Talmage · Mendocino County | — | — |
| Lg Electric Services INC | Eric Paul Langton | — | (707) 391 4820 | Electricians | Ukiah · Mendocino County | — | — |
| Liam Sugrue Construction | Liam Collins Sugrue | — | (707) 357 3915 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Lindorfer Construction | Benjamin Roberts Lindorfer | — | (510) 882 5277 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Little Lake Landscaping Construction | Douglas Lain Howard | — | (707) 972 5492 | Windows, patio, painters | Willits · Mendocino County | — | — |
| Little River Builders INC | James Dean Brown | — | (707) 937 1725 | GC, remodel, ADU | Littleriver · Mendocino County | — | — |
| Loial Electric | Edmund Loial Owen | — | (707) 621 1958 | Electricians | Hopland · Mendocino County | — | — |
| Lopez H D Construction | Jorge Agustin Lopez Osorio | — | (707) 357 5024 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Lotus Plumbing | Lotus Plumbing | — | (707) 849 7803 | Other | Ukiah · Mendocino County | — | — |
| Love Electric | Christopher Michael Love | — | (707) 391 5347 | Electricians | Ukiah · Mendocino County | — | — |
| Lucas Construction | David James Lucas | — | (707) 272 7851 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| Lucchesi Pump Irrigation | Luke Thomas Lucchesi | — | (707) 272 2661 | Other | Redwood Valley · Mendocino County | — | — |
| Lucchetti Construction | Anthony Michael Lucchetti | — | (707) 489 5572 | Other | Hopland · Mendocino County | — | — |
| Lucchetti Earthworks | Lucchetti Earthworks | — | (707) 391 4634 | Other | Redwood Valley · Mendocino County | — | — |
| Lucchetti Excavating | Lucchetti Excavating | lucchettiexcavating@gmail.com | (707) 463 0907 | Other | Ukiah · Mendocino County | — | — |
| Lyssand Construction | Lyssand Rolf | — | (707) 489 8448 | GC, remodel, ADU | Hopland · Mendocino County | — | — |
| M B C Construction Co INC | Kenneth Alan Seckora | — | (707) 272 3201 | Other | Ukiah · Mendocino County | — | — |
| M B Construction | Miguel Angel Bocel Sanchez | — | (707) 357 5701 | Other roofers | Fort Bragg · Mendocino County | — | — |
| M D's Quality Painting First Coat Plus | Michael Gerard Dehnert | — | (707) 477 1193 | Windows, patio, painters | Ukiah · Mendocino County | — | — |
| M G M Concrete | M G M Concrete | — | (707) 489 4025 | Other | Ukiah · Mendocino County | — | — |
| M J B Construction | Matthew Jason Brown | — | (707) 272 7178 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| M J Custom Design | M J Custom Design | — | (707) 435 4841 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| M L Electric | Larson Merle | — | (707) 357 0488 | Electricians | Fort Bragg · Mendocino County | — | — |
| M Mason Renovations | M Mason Renovations | — | (707) 548 1874 | GC, remodel, ADU | Gualala · Mendocino County | — | — |
| M S Thornton Construction | Mark Steven Thornton | — | (707) 272 3469 | GC, remodel, ADU | Redwood Valley · Mendocino County | — | — |
| Maki Construction | William Thomas Maki | info@maki-construction.com | (707) 621 1404 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| Malsom Construction | Kyle Steven Malsom | — | (707) 962 9231 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Maltas Construction LLC | Madrone Roben Maltas | mmaltas@maltasconstruction.com | (707) 272 3848 | GC, remodel, ADU | Redwood Valley · Mendocino County | — | — |
| Mangino Electric INC | Chris Mangino | — | (707) 367 1993 | Electricians | Ukiah · Mendocino County | — | — |
| Marcels Painting | Marcels Painting | — | (707) 813 7084 | Windows, patio, painters | Fort Bragg · Mendocino County | — | — |
| Marco A Chavoya | Marco A Chavoya | — | (707) 621 2220 | GC, remodel, ADU | Talmage · Mendocino County | — | — |
| Mark Berkich Plumbing | Mark Berkich Plumbing | — | (707) 895 2640 | Other | Comptche · Mendocino County | — | — |
| Mark Oglesby Construction | Mark Anthony Oglesby | — | (208) 755 1908 | GC, remodel, ADU | Willits · Mendocino County | — | — |
| Marshall Diving Services | Kirk Lee Marshall | — | (707) 964 7490 | Other | Fort Bragg · Mendocino County | — | — |
| Martell Woodworks INC | Benjamin Robert Martell | — | (415) 730 4701 | Other | Mendocino · Mendocino County | — | — |
| Martinson Construction | Chad Russell Martinson | — | (707) 485 4372 | GC, remodel, ADU | Redwood Valley · Mendocino County | — | — |
| Marvins Garden Tree Service | Coni Faye Dixon | mgtree86@att.net | (707) 459 1940 | Tree | Willits · Mendocino County | — | — |
| Marz Engineering | Marz Engineering | — | (707) 856 3007 | Other | Redwood Valley · Mendocino County | — | — |
| Matas Welding And Fabrication LLC | Maxwell William Mata | — | (707) 391 9945 | Other | Redwood Valley · Mendocino County | — | — |