| Amperage Security INC | Issac Ampornrut | — | (877) 899 1491 | Alarm and generators | Fullerton · Orange County | — | — |
| Ample Construction | Haci Esat Karaaslan | — | (714) 454 4305 | GC, remodel, ADU | Yorba Linda · Orange County | — | — |
| Amplified Electric | Penaloza Bustos Williams | — | (714) 474 6494 | Electricians | Irvine · Orange County | — | — |
| Amplify Electric 80 | Arturo Jr Ortiz | — | (714) 618 3770 | Electricians | Irvine · Orange County | — | — |
| Ampower | Behnam Sean Manavi | — | (714) 505 3013 | GC, remodel, ADU | Tustin · Orange County | — | — |
| Amps Electric Ac/dc INC | Dan Costel Nemes | — | (949) 573 4133 | Electricians | Costa Mesa · Orange County | — | — |
| Ampz Electrical Services | Adam Christopher Ziegler | — | (714) 222 3911 | Electricians | Fountain Valley · Orange County | — | — |
| Ams Builders INC | Allen Russell Harristakis | — | (714) 492 2471 | GC, remodel, ADU | Tustin · Orange County | — | — |
| Ams Solutions INC | Alexander Michael Samsky | info@ams-solutions.com | (805) 816 1209 | GC, remodel, ADU | Costa Mesa · Orange County | — | — |
| Amtech Heating & Air INC | Paul Robert Chelealba | — | (800) 882 3019 | HVAC | Irvine · Orange County | — | — |
| Amtek Construction | Steven Alan Sayce | info@amtekconstruction.com | (562) 696 7111 | Electricians | Orange · Orange County | — | — |
| Amtran | Singh Amarjit | — | (714) 282 0700 | Electricians | Yorba Linda · Orange County | — | — |
| An All Around Plumbing Specialist | An All Around Plumbing Specialist | — | (714) 654 9104 | Other | Seal Beach · Orange County | — | — |
| An Hyung Bae | An Hyung Bae | — | (949) 478 9876 | Other | Irvine · Orange County | — | — |
| An Restoration | An Restoration | — | (562) 965 6130 | GC, remodel, ADU | Mission Viejo · Orange County | — | — |
| An's Quality Painting | Sung Yol An | — | (949) 735 3380 | Windows, patio, painters | Anaheim · Orange County | — | — |
| Anaheim Air LLC | Matthew Brian James | — | (909) 287 6846 | HVAC | Placentia · Orange County | — | — |
| Anaheim Carpet And Flooring | Matthew Gordon Mortimer | — | (714) 535 4084 | Other | Anaheim · Orange County | — | — |
| Anaheim Glass INC | William Harrison Brundige | — | (714) 535 4940 | Windows, patio, painters | Anaheim · Orange County | — | — |
| Anaheim Hills Plumbing LLC | Thomas John Otto | — | (714) 961 1100 | Other | Anaheim · Orange County | — | — |
| Anaheim Hills Tile Supply | Jennifer Lynne Floyd | — | (714) 283 8522 | Tile distributors | Anaheim · Orange County | — | — |
| Anaheim Refrigeration INC | Seung Joon Lee | — | (714) 328 8085 | HVAC | Anaheim · Orange County | — | — |
| Anaheim Screen & Glass | Daniel L Segura | — | (714) 635 9335 | Windows, patio, painters | Anaheim · Orange County | — | — |
| Anaheim Signs | Anaheim Signs | — | (714) 270 0322 | Other | Anaheim · Orange County | — | — |
| Anaheim Stone And Tile | Anaheim Stone And Tile | — | (714) 815 7574 | Other | Laguna Hills · Orange County | — | — |
| Anaheim Stone Works INC | Gabriel Fernando Silva | — | (714) 937 1195 | Other | Anaheim · Orange County | — | — |
| Anahiem Hills Electric Company | Steven Wayne Mezzell | — | (714) 315 4251 | Electricians | Yorba Linda · Orange County | — | — |
| Anand Patel | Anand Patel | — | (949) 413 4543 | GC, remodel, ADU | Orange · Orange County | — | — |
| Anastasi Builders | Amrin Michael Anastasi | michael@anastasibuilders.com | (714) 916 2992 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| Anaya's Custom Painting | Anaya's Custom Painting | — | (714) 356 9048 | Windows, patio, painters | Santa Ana · Orange County | — | — |
| Anchor Alarm | Anchor Alarm | — | (714) 968 9891 | Electricians | Fountain Valley · Orange County | — | — |
| Anchor Awning | Anchor Awning | — | (714) 363 6332 | Other | Orange · Orange County | — | — |
| Anchor Builders INC | Enrique Morales Lopez | — | (714) 592 5126 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| Anchor Electric Services INC | Robert Stephen Barchilon | robbarchilon@gmail.com | (949) 916 7117 | Electricians | Mission Viejo · Orange County | — | — |
| Anchor Remodel | Aaron Mathew Aguilera | info@anchorremodel.com | (816) 819-9690 | GC, remodel, ADU | Garden Grove · Orange County | — | — |
| Anchor Tenant Improvement Concepts | Anchor Tenant Improvement Concepts | — | (714) 351 9809 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| Anchor Wallworks | Anchor Wallworks | — | (714) 637 7848 | Other | Anaheim · Orange County | — | — |
| Anchor Wallworks LLC | Sean Francis Brennan | — | (714) 637 7848 | Other | Anaheim · Orange County | — | — |
| Anchor West Construction INC | William James David | — | (949) 492 8670 | GC, remodel, ADU | San Clemente · Orange County | — | — |
| Anchored Construction & Restoration INC | James Lloyd Castro | — | (909) 275 5818 | GC, remodel, ADU | Santa Ana · Orange County | — | — |