| Air Tube Transfer Systems INC | Monica Esther Sweet | — | (714) 363 0700 | Other | Orange · Orange County | — | — |
| Air Vista INC | Gary Norman Krautkramer | — | (714) 962 1699 | HVAC | Huntington Beach · Orange County | — | — |
| Air-Tro Inc. | Air-Tro Inc. | — | (626) 357-3535 | HVAC | Orange County · Orange County | — | — |
| Airband Construction & Landscape | Thomas Jung-Gu Ryu | — | (213) 200 3733 | GC, remodel, ADU | Fullerton · Orange County | — | — |
| Airco INC | Kavandi Mohsen | — | (949) 822 1100 | HVAC | Irvine · Orange County | — | — |
| Aircom Mechanical | Jospeh Daniel Rinelli | — | (800) 739 6500 | HVAC | Santa Ana · Orange County | — | — |
| Aircon Solutions | Aircon Solutions | service@airconsolutions.ca | (714) 975 1125 | HVAC | Irvine · Orange County | — | — |
| Aircon Solutions Heating And Cooling | Jose Adrian Lazo Villalobo | — | (714) 975 1125 | HVAC | Irvine · Orange County | — | — |
| Airflow Solutions Heating & Air Cond | Martinez Geovanni | — | (949) 842 3855 | HVAC | Lake Forest · Orange County | — | — |
| Airhero Oc | Airhero Oc | sales@airherooc.com | (747) 290 4314 | HVAC | Newport Beach · Orange County | — | — |
| Airlink International | Frank Andrew Marchette | — | (714) 632 3020 | Other | Anaheim · Orange County | — | — |
| Airnizer Ca INC | Yauheni Kobak | — | (949) 880 9641 | HVAC | Ladera Ranch · Orange County | — | — |
| Airotech | Benjamin Khazraei | — | (949) 209 6473 | HVAC | Foothill Ranch · Orange County | — | — |
| Airpoint Heating & Air Conditioning | Robert David Leath | — | (844) 424 7764 | HVAC | Los Alamitos · Orange County | — | — |
| Airport Lock & Safe | Matthew John Minardi | — | (949) 833 2034 | Other | Irvine · Orange County | — | — |
| Airton Construction | Airat Tonduvai | — | (714) 703 9285 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Airtronix INC | Mattia Chemolli | — | (949) 679 5571 | HVAC | Santa Ana · Orange County | — | — |
| Ais Surveillance INC | Jong Seng Lee | — | (949) 922 0662 | Other | Irvine · Orange County | — | — |
| Aishola Remodeling | Elis Akylbekov | office@aisholaremodeling.com | (541) 736 6166 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Aj Alarm Systems | Aj Alarm Systems | al@ajalarmsystems.com | — | Alarm and generators | Orange · Orange County | — | — |
| Aj Cabinets | Aj Cabinets | — | (714) 458 4087 | Other | Anaheim · Orange County | — | — |
| Aj Concrete Services | Valencia-corona Antonio | — | (714) 554 9269 | Other | Santa Ana · Orange County | — | — |
| Aj Fence Works | Aj Fence Works | — | (949) 294 2543 | Other | Costa Mesa · Orange County | — | — |
| Aj's Duct Services INC | Tenorio Jorge Rivera | — | (714) 851 9432 | Other | Fullerton · Orange County | — | — |
| Ajax Construction INC | Nancy Jing Bai | — | (949) 837 8999 | GC, remodel, ADU | Laguna Hills · Orange County | — | — |
| Ajl Builders INC | Russell Nemo Venanzi | — | (714) 878 6067 | GC, remodel, ADU | Tustin · Orange County | — | — |
| Ajm Construction Services | Michael Joseph Tucker | — | (714) 863 9573 | Windows, patio, painters | Fountain Valley · Orange County | — | — |
| Ajm Contractor Services | Andrew Joseph Mastroianni | — | (949) 887 9017 | GC, remodel, ADU | Newport Beach · Orange County | — | — |
| Ajm Engineering | Ajm Engineering | — | (949) 842 6110 | Other | Laguna Niguel · Orange County | — | — |
| Ajn Electric INC | Andrew John Nunez | — | (714) 782 4740 | Electricians | Santa Ana · Orange County | — | — |
| Ajs Construction | Anthony Joseph Stoltze | — | (323) 309 0627 | GC, remodel, ADU | San Clemente · Orange County | — | — |
| Ajusco Drywall | Ajusco Drywall | — | (714) 296 5342 | Other | Tustin · Orange County | — | — |
| Ak Designs | Ak Designs | — | (213) 298 6918 | GC, remodel, ADU | Buena Park · Orange County | — | — |
| Ak Hardwood Floors | Ak Hardwood Floors | — | (714) 684 9980 | Other | Anaheim · Orange County | — | — |
| Akana Wood Design INC | Alfred Aki Akana | — | (714) 895 7150 | Other | Westminster · Orange County | — | — |
| Akdnc INC | Harry Sang Keal | — | (562) 714 5114 | GC, remodel, ADU | Cypress · Orange County | — | — |
| Akf Construction INC | Abdulkarim Fateh | info@akfconstruction.com | (714) 722 5247 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Akil Construction | Akil Kousay | — | (714) 470 4647 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Akins Company | Jay Bennett Akins | — | (949) 933 1685 | GC, remodel, ADU | Costa Mesa · Orange County | — | — |
| Akins Homes | Jay Bennett Akins | info@akinshomes.com | (949) 715 5445 | GC, remodel, ADU | Corona Del Mar · Orange County | — | — |