| Mike Naslund Concrete Construction | Michael John Naslund | — | (707) 319 1205 | Other | Napa · Napa County | — | — |
| Mike's Plumbing | Mike's Plumbing | — | (707) 320 3807 | Other | Napa · Napa County | — | — |
| Mike's Tree Service | David James Howe | — | (707) 226 2507 | Tree | Napa · Napa County | — | — |
| Millennium Painting | Millennium Painting | — | (707) 252 9415 | GC, remodel, ADU | Napa · Napa County | — | — |
| Miller Signs | Mark Edward Miller | — | (707) 647 2025 | HVAC | American Canyon · Napa County | — | — |
| Mitchell's Landscaping | Mitchell's Landscaping | — | (707) 334 9424 | Windows, patio, painters | American Canyon · Napa County | — | — |
| Modern Method Roofing Co INC | Bret Joseph Hummer | support@modernmethodroofing.com | (707) 255 8090 | Other roofers | Napa · Napa County | — | — |
| Mogino Group INC | Brent David Morgan | info@moginogroup.com | (888) 270 7337 | GC, remodel, ADU | Napa · Napa County | — | — |
| Mohammad Mustafa Afzal | Mohammad Mustafa Afzal | — | (925) 854 7400 | GC, remodel, ADU | Napa · Napa County | — | — |
| Monger Painting | Monger Painting | — | (707) 252 8425 | Windows, patio, painters | Napa · Napa County | — | — |
| Monticello Electric | Joe William Gonzales | — | (707) 514 8184 | Electricians | Napa · Napa County | — | — |
| Moore Creative Construction INC | Daniel Ethan Moore | — | (530) 448 1505 | GC, remodel, ADU | Napa · Napa County | — | — |
| More Painting | More Painting | morepaintingcs@gmail.com | (707) 235 6104 | Windows, patio, painters | Napa · Napa County | — | — |
| Morelia Landscape & Service | Miguel Arreola Acosta | — | (707) 252-4246 | Windows, patio, painters | Napa · Napa County | — | — |
| Morrison Cazares Boyer Construction INC | Allen Gordon Boyer | — | (707) 944 0307 | Other | Yountville · Napa County | — | — |
| Morrow Plumbing And Drain Service | Benjamin James Morrow | — | (541) 621 5667 | Other | Napa · Napa County | — | — |
| Mr Fix | Mr Fix | — | (707) 246 5770 | HVAC | Yountville · Napa County | — | — |
| Mr Home Improvement | Mr Home Improvement | — | (707) 363 1402 | GC, remodel, ADU | Napa · Napa County | — | — |
| Mri Heating And Air Conditioning | Mri Heating And Air Conditioning | — | (707) 685 4776 | HVAC | Napa · Napa County | — | — |
| Mudworks Drywall | Mudworks Drywall | — | (707) 287 3676 | Other | Napa · Napa County | — | — |
| Myles Davis Electric Incorporated | Myles Stephen Davis | — | (707) 224 9361 | Electricians | Napa · Napa County | — | — |
| N A S Landscapes | N A S Landscapes | — | (707) 501 0126 | Windows, patio, painters | Napa · Napa County | — | — |
| Napa Artisan Builders | Napa Artisan Builders | — | (707) 912-0688 | GC, remodel, ADU | Napa · Napa County | — | — |
| Napa Auto Parts - Encinitas | Napa Auto Parts - Encinitas | — | (760) 753-5597 | HVAC | Encinitas · Napa County | — | — |
| Napa Auto Parts - Escondido | Napa Auto Parts - Escondido | — | (760) 740-2100 | HVAC | Escondido · Napa County | — | — |
| Napa Auto Parts - Fallbrook | Napa Auto Parts - Fallbrook | — | (760) 728-8484 | Windows, patio, painters | Fallbrook · Napa County | — | — |
| Napa Auto Parts - Lakeside | Napa Auto Parts - Lakeside | — | (619) 561-4400 | Restoration | Lakeside · Napa County | — | — |
| Napa Auto Parts - Oceanside | Napa Auto Parts - Oceanside | — | (760) 722-8243 | HVAC | Oceanside · Napa County | — | — |
| Napa Auto Parts - Poway | Napa Auto Parts - Poway | — | (858) 679-3540 | HVAC | Poway · Napa County | — | — |
| Napa Auto Parts - San Marcos | Napa Auto Parts - San Marcos | — | (760) 736-6000 | HVAC | San Marcos · Napa County | — | — |
| Napa Auto Parts - Temecula | Napa Auto Parts - Temecula | — | (951) 296-0077 | Windows, patio, painters | Temecula · Napa County | — | — |
| Napa Build INC | Anguiano Rafael Vargas | napabuild@gmail.com | (707) 287 0014 | GC, remodel, ADU | Napa · Napa County | — | — |
| Napa County Builders | Napa County Builders | — | (707) 474 2702 | GC, remodel, ADU | Napa · Napa County | — | — |
| Napa County Building Inspection | Napa County Building Inspection | — | (707) 253-4417 | Inspectors | Napa · Napa County | — | — |
| Napa Electric | Napa Electric | information@napaelectric.com | — | Electricians | Napa · Napa County | — | — |
| Napa Electric Shop | Perez Ruben | information@napaelectric.com | (707) 252 6611 | Electricians | Napa · Napa County | — | — |
| Napa Floor Company | Alan Ainsley Booth | — | (707) 732 6075 | Other | Napa · Napa County | — | — |
| Napa Marble & Granite Works INC | Stephen Jerome Simich | napamarblegranite@yahoo.com | (707) 226 8484 | Other | Napa · Napa County | — | — |
| Napa Paint | Napa Paint | — | (707) 333 1811 | Windows, patio, painters | Napa · Napa County | — | — |
| Napa Pest Control Pros | Napa Pest Control Pros | info@napapestcontrolpros.com | (707) 230-6565 | Pest, tile roofs | Napa · Napa County | — | — |