| Alternative Landscaping Incorporated | Humberto Najera Ruiz | — | (714) 438 0580 | Windows, patio, painters | Santa Ana · Orange County | — | — |
| Alterra Floors LLC | Craig Alan Maurer | — | (949) 610 3607 | Other | Santa Ana · Orange County | — | — |
| Altin Electric INC | Emamgholizadeh Mehdi | info@altinelectric.com | (949) 828 2848 | Electricians | Aliso Viejo · Orange County | — | — |
| Alton Air Conditioning | Alton Air Conditioning | — | (714) 273 0910 | HVAC | Dana Point · Orange County | — | — |
| Altru Construction | Brad Warren Oien | — | (714) 768 4914 | Other | Fountain Valley · Orange County | — | — |
| Alu - Glass INC | Juan Jesus Rubio Plascencia | — | (714) 512 7649 | Windows, patio, painters | Tustin · Orange County | — | — |
| Alum Works | Andrew Lionel Leclerc | — | (301) 471 6811 | GC, remodel, ADU | San Clemente · Orange County | — | — |
| Alumascape | Abdul Joseph Sekander | — | (949) 293 2800 | Other | Corona Del Mar · Orange County | — | — |
| Alux Pro Painting | Alux Pro Painting | — | (714) 722 3181 | Windows, patio, painters | Santa Ana · Orange County | — | — |
| Alva Plumbing | Alva Plumbing | — | (714) 323 3381 | Other | Garden Grove · Orange County | — | — |
| Alvarez Alvarez Roofing INC | Alvarez Higinio Alvarez | — | (714) 805 3037 | Other roofers | Santa Ana · Orange County | — | — |
| Alvarez Brothers Tile Stone | Daniel Alvarez-Jarquin | — | (714) 391 5450 | Other | Anaheim · Orange County | — | — |
| Alvarez Painting & Decor INC | Angela Vitalina Alvarez Machuca | — | (714) 600 2517 | Windows, patio, painters | Anaheim · Orange County | — | — |
| Alvarez Plastering INC | Jorge Victor Alvarez Moreno | — | (714) 824 0674 | Other | Santa Ana · Orange County | — | — |
| Alvin Yuu Tabata | Alvin Yuu Tabata | — | (310) 753 9135 | Other | Fullerton · Orange County | — | — |
| Alwan American Construction | Riad Farouk Alwan | — | (714) 883 9907 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| Always Green Synthetic Grass INC | Conrad Luis Macedo | — | (714) 309 5790 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| Am Best Construction | Kye Myung Cho | — | (714) 323 3001 | HVAC | Brea · Orange County | — | — |
| Am Best Painting | Am Best Painting | — | (714) 549 9419 | Windows, patio, painters | Santa Ana · Orange County | — | — |
| Am Contractors INC | Ante Ivan Marijanovic | — | (562) 277 6699 | GC, remodel, ADU | Seal Beach · Orange County | — | — |
| Am Pro Construction | Majid Parvin | info@amproconstruction.com | (949) 331 4900 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Am Sunshine General Contractor INC | Jose Delfino Amaro Rojas | — | (714) 468 4105 | GC, remodel, ADU | Orange · Orange County | — | — |
| Am-kor Fire Protection Co INC | Jason Taesung Kim | — | (714) 441 1537 | Other | Fullerton · Orange County | — | — |
| Am-tex Construct Design | Am-tex Construct Design | — | (949) 247 9890 | GC, remodel, ADU | Lake Forest · Orange County | — | — |
| Ama Electric | Ahmed Mouhannad Akkad | — | (949) 527 8717 | Electricians | Irvine · Orange County | — | — |
| Amador Plastering | Amador Plastering | — | (714) 591 3093 | Other | Anaheim · Orange County | — | — |
| Amali Engineering Contractors INC | Yousef Raad Najeeb Habhab | — | (650) 302 2842 | GC, remodel, ADU | Fullerton · Orange County | — | — |
| Amana Construction | Abdelbasit M Aljazzar | — | (909) 223 8048 | GC, remodel, ADU | Cypress · Orange County | — | — |
| Amano Mcgann INC | Alex William Jr Suhovy | — | (714) 282 3500 | Other | Yorba Linda · Orange County | — | — |
| Amar Property Services INC | Covarrubias Ariel Marquez | — | (714) 225 1861 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| Amax Builders | Amax Builders | — | (949) 232 8117 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Amazing Plumbing | Amazing Plumbing | — | (714) 879 0962 | Other | Cypress · Orange County | — | — |
| Amazing Pools & Spas INC | Ray Eben Hollenbeck | — | (714) 717 7932 | Pool | Cypress · Orange County | — | — |
| Amazing Rooter | Victor A Cancino Cisneros | — | (714) 215 7439 | Other | Buena Park · Orange County | — | — |
| Amazingpros Services | Peter Yoo Kim | — | (213) 570 1100 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| Amazon Garage Doors And Gates | Etay Abraham Aroshas | — | (844) 777 3677 | Other | Santa Ana · Orange County | — | — |
| Amber Electric | Amber Michelle Armbruster | anapbm@gmail.com | (562) 762 6857 | Electricians | Yorba Linda · Orange County | — | — |
| Amber Electric LLC | Benjamin Bernard Russelle | anapbm@gmail.com | (714) 650 2744 | Electricians | Buena Park · Orange County | — | — |
| Amber Ornamental Iron | Jose Alfredo Cossio | — | (949) 651 0255 | Other | Fullerton · Orange County | — | — |
| Amberline Gc INC | Audrius Pranas Chmeliovas | — | (206) 769 1429 | GC, remodel, ADU | Cypress · Orange County | — | — |