| A's Tree Service | Segura Areli | — | (714) 296 2598 | Tree | Placentia · Orange County | — | — |
| A+ Construction | Jeffrey Scott Orman | — | (714) 350 8232 | GC, remodel, ADU | Aliso Viejo · Orange County | — | — |
| A+ Smart Plumbing INC | Jung Woo Han | — | (516) 580 1005 | Other | Irvine · Orange County | — | — |
| A-1 Affordable Property Services | Vazquez-guerrero Oscar | — | (714) 585 8140 | GC, remodel, ADU | Aliso Viejo · Orange County | — | — |
| A-1 Apache Plumbing | A-1 Apache Plumbing | — | (323) 385 8763 | GC, remodel, ADU | La Habra · Orange County | — | — |
| A-1 Fence | Gilberto Ontiveros | — | (714) 630 3390 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A-1 Manteq Electronic Systems INC | Martin Marian Radu | — | (949) 433 0306 | Electricians | Costa Mesa · Orange County | — | — |
| A-1 Painting Concepts | A-1 Painting Concepts | — | (714) 292 2953 | GC, remodel, ADU | Fullerton · Orange County | — | — |
| A-1 Painting Concepts INC | Wang Sik Lim | — | (714) 879 4000 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A-1 Speedy Rooter And Plumbing | Edwin Victor Montalvo | — | (714) 249 0422 | Other | Westminster · Orange County | — | — |
| A-3 Construction INC | Edwin Santana | — | (714) 597 5865 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| A-american Plumbing Company | Gregory Mitchell Saenz | — | (949) 355 6770 | Other | Seal Beach · Orange County | — | — |
| A-ev Installs | Liliana Rodriguez Phillips | — | (949) 469 4443 | EV chargers | Huntington Beach · Orange County | — | — |
| A-plus Businesses INC | Stephen Craig Peake | — | (714) 709 7730 | GC, remodel, ADU | Rancho Santa Margarita · Orange County | — | — |
| A-plus Quality Construction | Noory Ismatullah | — | (310) 612 1354 | GC, remodel, ADU | Irvine · Orange County | — | — |
| A-pro Security Services INC | Gregory Kipnis | — | (949) 635 0300 | Alarm and generators | Trabuco Canyon · Orange County | — | — |
| A-z Property Services | Jose Andrew Galindo | — | (714) 910 3160 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A1 Hardwood Flooring LLC | Petr Hilek | — | (949) 433 4949 | Other | Anaheim · Orange County | — | — |
| A1 International Tv Sales & Service INC DBA Nuvision Construction | Zafer Khalil Bayaa | — | (714) 544 6961 | GC, remodel, ADU | Tustin · Orange County | — | — |
| A1 Yes Construction INC | Simcha Desta | — | (949) 473 0874 | GC, remodel, ADU | Tustin · Orange County | — | — |
| A2 Communication | Firooznam Arash | — | (714) 812 9384 | Other | Yorba Linda · Orange County | — | — |
| A2 Construction | Anthony Julian Aguilera | info@a2-construction.com | (949) 280 8810 | GC, remodel, ADU | San Clemente · Orange County | — | — |
| A2 Contracting INC | Andrew Joseph Adair | — | (949) 599 8328 | GC, remodel, ADU | Rancho Santa Margarita · Orange County | — | — |
| A2 Energy Services INC | William Ross Vallone | — | (949) 828 7490 | Electricians | Laguna Beach · Orange County | — | — |
| A2z Developers INC | Nir Bezalel | — | (714) 509 5045 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| A2z Painting INC | Joel Mendoza | — | (714) 830 8134 | Windows, patio, painters | Santa Ana · Orange County | — | — |
| A2z Tech Communications Cabling | A2z Tech Communications Cabling | — | (951) 581 4288 | Other | Anaheim · Orange County | — | — |
| A2z Wiring Electric | Jose Guadalupe Lorenzo | — | (714) 943 0944 | Electricians | Santa Ana · Orange County | — | — |
| Aa Atlas Plumbing Heating & Air Conditioning | Randy Robert Sousa | — | (714) 970 5885 | HVAC | Yorba Linda · Orange County | — | — |
| Aa Construction | Serrano Alberto | — | (909) 452 0397 | GC, remodel, ADU | Costa Mesa · Orange County | — | — |
| Aa Kuem Kang Construction Co | John Chong Chol Lee | — | (714) 794 7600 | GC, remodel, ADU | Garden Grove · Orange County | — | — |
| Aa Modern Construction INC | Kazem Kashizadeh | — | (949) 400 2470 | GC, remodel, ADU | Laguna Niguel · Orange County | — | — |
| Aa Pacific Concrete Cleaning | Aa Pacific Concrete Cleaning | — | (949) 235 1338 | Other | San Clemente · Orange County | — | — |
| Aa Plumbing Remodel LLC | Robert E Mangold | — | (949) 293 8826 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Aa Refrigeration Corp | Agustin Ayala | interested@domainmarket.com | (562) 773 6857 | HVAC | La Habra · Orange County | — | — |
| Aaa Awnings INC | Michael Stephen Lewis | — | (714) 597 6920 | Windows, patio, painters | Garden Grove · Orange County | — | — |
| Aaa Construction & Remodeling INC | Mario Diaz | — | (714) 865 3509 | GC, remodel, ADU | Orange · Orange County | — | — |
| Aaa Construction And Remodeling | Assouline Yaniv | — | (833) 420 7378 | GC, remodel, ADU | Laguna Hills · Orange County | — | — |
| Aaa Demolition INC | Rodriguez Raymundo | — | (714) 817 0011 | Other | Anaheim · Orange County | — | — |
| Aaa Electric Services | Amir Houshang Anvari | — | (714) 269 5867 | Electricians | Coto De Caza · Orange County | — | — |