| A New Perspective Construction | Stephen Ray Jr| Perron Steve Perron | — | (408) 966 8275 | GC, remodel, ADU | Milpitas · Santa Clara County | — | — |
| A New Star Painting Co | Juan Jose Nieto | — | (714) 414 1091 | Windows, patio, painters | Yorba Linda · Orange County | — | — |
| A New View Windows & Doors INC | Cash Wrede Cockerill | — | (714) 953 7663 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A Nicer Finish Painting | A Nicer Finish Painting | — | (530) 264 6982 | Windows, patio, painters | Cedar Ridge · Nevada County | — | — |
| A Noll INC DBA Ajn Construction | Alexander Johan Noll | — | (530) 622 5429 | GC, remodel, ADU | Placerville · El Dorado County | — | — |
| A O - Kay Glass And Screen | Christopher Micheal Kay | — | (909) 874 1140 | Windows, patio, painters | Rialto · San Bernardino County | — | — |
| A O C Construction INC | Czerniewski Wojciech | — | (619) 226 0772 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| A O C Marble & Granite INC | Mahdad Fard-Ghassemi | — | (714) 535 0800 | Other | Anaheim · Orange County | — | — |
| A O C Masonry | Albert Orlando Cubias | — | (714) 476 5133 | Other | Anaheim · Orange County | — | — |
| A O Construction & Renovations | Julio Cesar Aguirre Almirez | — | (909) 257 7556 | GC, remodel, ADU | San Bernardino · San Bernardino County | — | — |
| A O Construction Clean Up INC | Antonio Aguayo Ornelas | — | (818) 612 8847 | Other | Valencia · Los Angeles County | — | — |
| A O Dowd Plumbing INC | Jason Matthew Dowd | — | (909) 684 1915 | Other | Fontana · San Bernardino County | — | — |
| A O Electric | Ochoa Arthur | — | (909) 810 9069 | Electricians | Yucaipa · San Bernardino County | — | — |
| A O Electric INC | Arthur Allen Osha | — | (805) 688 1345 | Electricians | Santa Ynez · Santa Barbara County | — | — |
| A O G Plumbing INC | Orozco Guerrero Alberto | — | (707) 953 2541 | Other | Rohnert Park · Sonoma County | — | — |
| A O Heating & Air - Conditioning | Moon Kyung Sik | — | (408) 930 2809 | HVAC | San Jose · Santa Clara County | — | — |
| A O Jones Paving INC | John Larry Jones | anapbm@gmail.com | (925) 439 7027 | Other | Pittsburg · Contra Costa County | — | — |
| A O Kraft INC | Andrew Nicholas Jr Ornelas | — | (909) 915 4310 | GC, remodel, ADU | San Bernardino · San Bernardino County | — | — |
| A O L Heating & Air INC | Anjel Avraham | — | (818) 705 0000 | HVAC | Chatsworth · Los Angeles County | — | — |
| A O L Painting | A O L Painting | — | (925) 597 2417 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| A O Masonry INC | Oros-cuin Arnulfo | — | (760) 989 8500 | Other | Coachella · Riverside County | — | — |
| A O Plumbing | Adam Wright Osterbuhr | — | (619) 507 5268 | Other | La Mesa · San Diego County | — | — |
| A O Reed & Co LLC | Steven Brent Andrade | info@aoreed.com | (858) 565 4131 | HVAC | San Diego · San Diego County | — | — |
| A O Torres Construction Co | Alejandro Ortiz| Torres Alex Torres | — | (760) 834 5870 | HVAC | Indio · Riverside County | — | — |
| A O West Contracting INC | Alphonso Olmos | — | (951) 741 1413 | GC, remodel, ADU | Corona · Riverside County | — | — |
| A Ochoa's Painting INC | Alex Ochoa | — | (619) 210 3004 | Windows, patio, painters | Chula Vista · San Diego County | — | — |
| A Okeha Construction | Malakai Tohi Vaikona | — | (408) 373 6429 | GC, remodel, ADU | San Jose · Santa Clara County | — | — |
| A Omega Termite & Construction Corp | Victor Manuel Jr Herrera | — | (949) 379 0469 | GC, remodel, ADU | Irvine · Orange County | — | — |
| A One Designs Co | Adam A Ghadiri | — | (949) 350 5556 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| A One Fence/gate Repair | A One Fence/gate Repair | — | (951) 256 6384 | Other | Corona · Riverside County | — | — |
| A One Hoe Rental | Dennis Jay Letteer | — | (510) 760 2695 | Other | Manteca · San Joaquin County | — | — |
| A Ortega Construction | Ortega Lopez Abelardo | — | (714) 388 0034 | GC, remodel, ADU | Hawaiian Gardens · Los Angeles County | — | — |
| A Oteiza Landscape Management INC | Albert Alberto Oteiza | — | (650) 224 0098 | Windows, patio, painters | San Jose · Santa Clara County | — | — |
| A P 1 Leak Detection INC | Joe Luis| Aguilar-saldana Jose L Aguilar | — | (818) 675 2135 | Pool | Canyon Country · Los Angeles County | — | — |
| A P A General Building Construction | Ashot Petrosyan | — | (818) 482 3815 | GC, remodel, ADU | Sun Valley · Los Angeles County | — | — |
| A P Air Systems | Mark Arkadyevich Fridlyand | — | (408) 733 2000 | HVAC | Campbell · Santa Clara County | — | — |
| A P Alarm INC | Paval Adrian | — | (916) 791 4141 | Alarm and generators | Roseville · Placer County | — | — |
| A P American Construction Co | Perez-najera Angel | — | (818) 581 1285 | GC, remodel, ADU | Canoga Park · Los Angeles County | — | — |
| A P Backhoe & Trucking Service INC | Antonio Teixeira Poipao | — | (925) 864 4344 | Other | Placerville · El Dorado County | — | — |
| A P Bathtub Painting | A P Bathtub Painting | — | (714) 805 4152 | Windows, patio, painters | Santa Ana · Orange County | — | — |