| Aquastar Pool Products | Aquastar Pool Products | — | (877) 768-2717 | Pool | Ventura · Ventura County | — | — |
| Aquastructure | Erik William Thiele | — | (818) 535 5840 | Pool | Moorpark · Ventura County | — | — |
| Aquazur INC | Mas Gianni Dal | — | (310) 795 9593 | Pool | Camarillo · Ventura County | — | — |
| Aqueos Corporation | Theodore Kenneth Iv Roche | contact@aqueos.com | (337) 714 0033 | Other | Ventura · Ventura County | — | — |
| Ara Construction | Austin Robert Simonson-adam | info@araconstruction.com | (805) 377 6993 | GC, remodel, ADU | Ojai · Ventura County | — | — |
| Araquin Builder | Araquin Builder | — | (818) 497 5803 | GC, remodel, ADU | Camarillo · Ventura County | — | — |
| Arb Artisan Plaster | Beto Rivera | — | (805) 844 4739 | Other | Oxnard · Ventura County | — | — |
| Arbo Lo Co Tree Care | Lorin Daniel Moll | — | (805) 443 1265 | Other | Ventura · Ventura County | — | — |
| Arboles Care Tree Service INC | Ivan Rodriguez | — | (805) 485 0640 | Tree | Oxnard · Ventura County | — | — |
| Arbor Artist INC | Jeremy Levi Kenton | — | (805) 798 1463 | Tree | Ojai · Ventura County | — | — |
| Arbor Light INC DBA Kristopher Pohlman Painting | Kristopher David Pohlman | — | (805) 404 0409 | GC, remodel, ADU | Simi Valley · Ventura County | — | — |
| Arborist Crew Services INC | Joel Christopher Brinkman | — | (818) 634 5102 | Tree | Camarillo · Ventura County | — | — |
| Arc Plumbing | Arc Plumbing | — | (805) 469 6973 | Other | Camarillo · Ventura County | — | — |
| Arcade Glass Company | Sarah Lynn Turner | — | (805) 646 1093 | Windows, patio, painters | Ojai · Ventura County | — | — |
| Arcade Glass Company INC | Sarah Lynn Turner | — | (805) 646 1093 | Windows, patio, painters | Ojai · Ventura County | — | — |
| Arcadio Nava Almanza | Arcadio Nava Almanza | — | (805) 766 1691 | Other | Ventura · Ventura County | — | — |
| Arce General Engineering Construction | Raul Jr Arce | — | (805) 889 3956 | Other | Oxnard · Ventura County | — | — |
| Arce's Roofing | Arce Fernandez Manuel | — | (805) 890 3622 | Other roofers | Ventura · Ventura County | — | — |
| Archer Pool Care And Repair | Archer Pool Care And Repair | — | (805) 320 4547 | Pool | Ventura · Ventura County | — | — |
| Architectural Woodworks | Architectural Woodworks | — | (805) 340 6624 | GC, remodel, ADU | Santa Paula · Ventura County | — | — |
| Archon Protection Inc. | Archon Protection Inc. | — | (800) 274-5717 | Alarm and generators | Ventura · Ventura County | — | — |
| Archway Garage Doors | Rick Dean Burk | — | (805) 578 6015 | Other | Simi Valley · Ventura County | — | — |
| Archwood Builders & Development INC | Barry Dean Paster | — | (818) 429 4739 | GC, remodel, ADU | Oxnard · Ventura County | — | — |
| Ardalan Construction Company INC | Mozafar Ardalan | — | (805) 496 7273 | GC, remodel, ADU | Thousand Oaks · Ventura County | — | — |
| Area Electric | Craig Byron Area | — | (805) 732 7091 | Electricians | Camarillo · Ventura County | — | — |
| Arellano Masonry INC | Jeffrey Christopher Arellano | arellanomasonryinc@gmail.com | (805) 732 7973 | Other | Simi Valley · Ventura County | — | — |
| Arelli Construction | Anthony David Capparelli | — | (805) 290 7906 | GC, remodel, ADU | Camarillo · Ventura County | — | — |
| Aria Behvar | Aria Behvar | — | (818) 448 0726 | GC, remodel, ADU | Simi Valley · Ventura County | — | — |
| Arias Concrete | Arias Concrete | — | (805) 377 9076 | Other | Oxnard · Ventura County | — | — |
| Arias Construction | Arias E Armando | — | (805) 207 4676 | GC, remodel, ADU | Camarillo · Ventura County | — | — |
| Aries Development INC | James Arthur Springer | stepanova@aries-development.com | (805) 320 6855 | Electricians | Ventura · Ventura County | — | — |
| Arimo's Cabinet Works | Arimo's Cabinet Works | — | (805) 890 2645 | Other | Oxnard · Ventura County | — | — |
| Arjays Gotcha Covered | Donna Ann Buice | — | (805) 642 2300 | Other | Camarillo · Ventura County | — | — |
| Ark Professional Painting | Ark Professional Painting | — | (805) 206 9260 | Windows, patio, painters | Newbury Park · Ventura County | — | — |
| Arko Development INC | Edward Preston Arko | — | (818) 835 6690 | GC, remodel, ADU | Moorpark · Ventura County | — | — |
| Arko Steel | Arko Steel | — | (805) 529 1528 | Other | Moorpark · Ventura County | — | — |
| Arko Steel INC | Edward John Arko | — | (805) 529 1528 | Other | Moorpark · Ventura County | — | — |
| Arl General Engineering INC | Abraham Roberto Larios | — | (818) 739 9787 | Other | Simi Valley · Ventura County | — | — |
| Arlan Dax Rooks | Arlan Dax Rooks | — | (805) 275 6452 | Other | Ventura · Ventura County | — | — |
| Armoz Construction INC | Aroutin Panosian | — | (818) 521 2144 | GC, remodel, ADU | Simi Valley · Ventura County | — | — |