| A Sign-scape | A Sign-scape | — | (714) 470 1136 | Other | Santa Ana · Orange County | — | — |
| A T C Construction INC | Cory William Robertson | — | (949) 215 2987 | GC, remodel, ADU | Mission Viejo · Orange County | — | — |
| A T Dabasinskas Co LLC | Austin Thomas Dabasinskas | — | (714) 349 3016 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A T H Construction | Anthony Todd Hahner | — | (951) 538 0987 | GC, remodel, ADU | Yorba Linda · Orange County | — | — |
| A T L Electric | Thomas A Laluk | — | (714) 580 6163 | Electricians | Laguna Niguel · Orange County | — | — |
| A T P Audio/video & Electric | Christopher Ryan Topper | — | (949) 521 1310 | Electricians | Newport Beach · Orange County | — | — |
| A T Thompson Contractor | A T Thompson Contractor | — | (714) 458 2415 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| A To Z Building Solutions | Carlos Alberto Guillen | — | (949) 396 9236 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| A To Z Construction | Cao Derrick | — | (714) 775 1837 | GC, remodel, ADU | Westminster · Orange County | — | — |
| A To Z Electrical | Sorin Ioan Chis | — | (949) 315 5519 | Electricians | Laguna Hills · Orange County | — | — |
| A To Z General Contractors LLC | Arjanbir Singh Bhandal | — | (949) 400 4911 | GC, remodel, ADU | Aliso Viejo · Orange County | — | — |
| A Top En-counter | A Top En-counter | — | (714) 899 9858 | Other | Huntington Beach · Orange County | — | — |
| A V Apex Construction INC | Valencia Alejandro | — | (562) 293 8867 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A V Construction INC | Arees Raffi Akoubian | — | (714) 964 4838 | GC, remodel, ADU | Fountain Valley · Orange County | — | — |
| A V Culture | A V Culture | — | (714) 907 5075 | Other | Santa Ana · Orange County | — | — |
| A V Landscape LLC | Juan Llavel Vega | — | (714) 574 2606 | Windows, patio, painters | Orange · Orange County | — | — |
| A V Pro INC | Afshin Vaghef | — | (949) 888 4726 | GC, remodel, ADU | Mission Viejo · Orange County | — | — |
| A Viveros Painting | A Viveros Painting | — | (949) 285 6618 | Windows, patio, painters | Lake Forest · Orange County | — | — |
| A W & Sons INC | Anthony Aaron Jr Woodward | — | (562) 690 1505 | Other | San Clemente · Orange County | — | — |
| A W Construction | Alan Roy Weyrick | — | (714) 876 5150 | GC, remodel, ADU | Fountain Valley · Orange County | — | — |
| A W E Enterprises | Andrew Joseph Waian | — | (714) 606 1591 | Electricians | San Clemente · Orange County | — | — |
| A W H INC | Omar Adnan Al-Darraji | — | (562) 753 6829 | GC, remodel, ADU | Cypress · Orange County | — | — |
| A Wiring Man | A Wiring Man | — | (714) 990 8192 | Electricians | Fullerton · Orange County | — | — |
| A Z Concrete Design | A Z Concrete Design | — | (949) 872 0808 | Other | Silverado · Orange County | — | — |
| A&a Builder INC | Calvin Lam | — | (949) 803 8000 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| A&a Plumbing Solutions LLC | Angel Michael Robles | — | (949) 449 3287 | Other | Santa Ana · Orange County | — | — |
| A&a Property Management LLC | Adam Jacob Melville | — | (949) 379 9273 | GC, remodel, ADU | Laguna Hills · Orange County | — | — |
| A&b Pro Painting Co | Bryan Agustin Olguin Cigarroa | — | (949) 528 7349 | Windows, patio, painters | Mission Viejo · Orange County | — | — |
| A&c Global Construction | Ramirez Arturo Carrera | — | (714) 631 7676 | GC, remodel, ADU | Garden Grove · Orange County | — | — |
| A&d Masri INC | Mohamad Ali El Masri | — | (818) 620 2178 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A&m Painting & Decorating INC | Mandegari Amirshahin | — | (949) 412 5969 | Windows, patio, painters | Orange · Orange County | — | — |
| A&r Quality Construction INC | Victor Manuel Bonilla Perez | arqualityconst@gmail.com | (949) 243 4177 | GC, remodel, ADU | Lake Forest · Orange County | — | — |
| A&t Heating Cooling | A&t Heating Cooling | — | (714) 383 0303 | HVAC | Westminster · Orange County | — | — |
| A&w Builders INC | David Allen Wilson | awbuildersocal@gmail.com | (949) 680 9552 | GC, remodel, ADU | San Juan Capistrano · Orange County | — | — |
| A'alam Sadeghi | A'alam Sadeghi | — | (714) 776 5599 | Electricians | Orange · Orange County | — | — |
| A's & Sons Concrete | Andrew Jonathan Aguirre | — | (949) 549 9397 | Other | Santa Ana · Orange County | — | — |
| A's Contractor INC | Octavian Petrut | — | (800) 886 1594 | GC, remodel, ADU | Orange · Orange County | — | — |
| A's Custom Builder | A's Custom Builder | — | (949) 357 4969 | GC, remodel, ADU | Laguna Niguel · Orange County | — | — |
| A's Painting | De La Luz Gerardo Alcantara | — | (949) 344 0209 | Windows, patio, painters | Laguna Hills · Orange County | — | — |
| A's Professional Roofing INC | Aguilar Huipe Martin | — | (949) 903 4121 | Other roofers | Orange · Orange County | — | — |