| A P Consulting Engineers INC | Anthony Christopher Ponterio | — | (650) 773 5793 | GC, remodel, ADU | Hillsborough · San Mateo County | — | — |
| A Perez Construction | Alfonso Martin Perez | — | (650) 508 1569 | GC, remodel, ADU | San Carlos · San Mateo County | — | — |
| A Plus Building Maintenance LLC | Jose Luis Mendez | — | (650) 787 2977 | GC, remodel, ADU | South San Francisco · San Mateo County | — | — |
| A Plus Plumbing | Zaur Mukhamedovic Bolokov | aplusplumbingser@gmail.com | (415) 630 0077 | Electricians | Colma · San Mateo County | — | — |
| A Q Construction | Wah Kwan To | — | (510) 219 8228 | GC, remodel, ADU | Millbrae · San Mateo County | — | — |
| A R C Electric | Jordan L Suiter | — | (510) 414 3068 | Electricians | Foster City · San Mateo County | — | — |
| A R Construction | Milton Adolfo Rosales Choy | — | (415) 225 2267 | GC, remodel, ADU | San Mateo · San Mateo County | — | — |
| A R Electric | Antonio De Jesus Revuelta De Alba | — | (650) 681 7865 | Electricians | Redwood City · San Mateo County | — | — |
| A R Groth Co INC | Ann Mercedes Ossenberg | phil@argroth.com | (415) 468 3365 | Windows, patio, painters | Brisbane · San Mateo County | — | — |
| A R T Carpets & Vinyl | Michael Walter Boettcher | — | (650) 278 9103 | Other | Pacifica · San Mateo County | — | — |
| A Ravella Construction And Engineering | Andrew Joseph Ravella | — | (650) 483 7356 | GC, remodel, ADU | San Carlos · San Mateo County | — | — |
| A S G Complete Landscape & Maintenance INC | Gonzalez Antonio Sanchez | — | (650) 921 3141 | Windows, patio, painters | Redwood City · San Mateo County | — | — |
| A Schaefer Construction | Andrew Alfons Schaefer | — | (650) 240 6448 | GC, remodel, ADU | San Mateo · San Mateo County | — | — |
| A Storseter Construction | Andrew Bernard Storseter | — | (650) 784 5964 | GC, remodel, ADU | Millbrae · San Mateo County | — | — |
| A T Construction | Allan Macdonald Tate | — | (650) 208 2341 | GC, remodel, ADU | Redwood City · San Mateo County | — | — |
| A W Construction | Aaron Richard Wilkinson | — | (650) 503 9933 | GC, remodel, ADU | Menlo Park · San Mateo County | — | — |
| A X A Construction INC | Natalia Boldurescu | — | (415) 579 6031 | GC, remodel, ADU | Daly City · San Mateo County | — | — |
| A&r Electrical Services INC | Christopher Javier Avila Ruano | — | (650) 995 4520 | Electricians | Half Moon Bay · San Mateo County | — | — |
| A-1 Painting INC | Daniel Dwight Buss | — | (650) 589 8347 | Windows, patio, painters | South San Francisco · San Mateo County | — | — |
| A-a Lock & Alarm INC | James Bruce Mac Lachlan | — | (650) 326 9020 | Alarm and generators | Menlo Park · San Mateo County | — | — |
| A/c Electric Design INC | Cassar Anthony | — | (650) 333 1406 | Electricians | Redwood City · San Mateo County | — | — |
| A4 Homes | Christopher Michael Adams | — | (415) 318 0793 | GC, remodel, ADU | Menlo Park · San Mateo County | — | — |
| Aa Customs Proav INC | Divnov Alexei | — | (650) 762 9598 | Electricians | San Mateo · San Mateo County | — | — |
| Aa General Contractor | Aa General Contractor | — | (650) 274 8523 | GC, remodel, ADU | Redwood City · San Mateo County | — | — |
| Aa Networks Corp | Wai Lung Lui | — | (650) 872 1998 | Other | Burlingame · San Mateo County | — | — |
| Aaa Construction Co | Kim Yeol | yuriy@aaaconstruction.com | (415) 725 1728 | GC, remodel, ADU | San Bruno · San Mateo County | — | — |
| Aaron's Mechanical Heating And Cooling | Mario Renato Garcia | — | (650) 771 6945 | HVAC | Redwood City · San Mateo County | — | — |
| Ab Construction And Maintenance 777 | Moreno Abraham Barragan | — | (650) 346 0696 | GC, remodel, ADU | Redwood City · San Mateo County | — | — |
| Ab Mour Development | Ali Amirteymour | — | (650) 430 5552 | GC, remodel, ADU | San Mateo · San Mateo County | — | — |
| Abbey Roofing INC | Mark Christopher Dorst | — | (650) 697 2014 | Other roofers | San Mateo · San Mateo County | — | — |
| Abc Service | Torbanenko Artur | — | (650) 237 9095 | HVAC | Menlo Park · San Mateo County | — | — |
| Abc Tree Farms & Pick Of The Patch Pumpkins - Smno | Abc Tree Farms & Pick Of The Patch Pumpkins - Smno | info@abctreefarms.net | (650) 533-4936 | Tree | San Mateo · San Mateo County | — | — |
| Abc&d | Richard Harold Quinn | — | (510) 545 9016 | GC, remodel, ADU | Half Moon Bay · San Mateo County | — | — |
| Abcor Electro-mechanical | Abcor Electro-mechanical | — | (415) 290 7610 | Electricians | South San Francisco · San Mateo County | — | — |
| Abel Sandoval Painting | Abel Sandoval Painting | — | (415) 740 1611 | Windows, patio, painters | South San Francisco · San Mateo County | — | — |
| Abi Construction | Abi Necirvan | — | (415) 629 7673 | GC, remodel, ADU | San Mateo · San Mateo County | — | — |
| Abn Construction INC | Abner Nevai Fuentes Orozco | info@abnconstruction.com | (650) 346 9351 | GC, remodel, ADU | San Mateo · San Mateo County | — | — |
| Above All Roofing Services INC | Emile Francois L'hoir | info@aboveallroofingservices.com | (650) 622 9780 | Other roofers | San Carlos · San Mateo County | — | — |
| Abs Custom Builders | Abs Custom Builders | alex@abscustombuilders.com | (415) 465 3684 | GC, remodel, ADU | Pacifica · San Mateo County | — | — |
| Abs Plastering INC | Barrera Santiago Ambrocio | — | (650) 245 3482 | Other | San Mateo · San Mateo County | — | — |