| Api INC | Perez Victor | — | (714) 606 3668 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| Api Painting INC | Rosales Pedro Jaimes | — | (714) 318 3937 | Windows, patio, painters | Anaheim · Orange County | — | — |
| Apitz Construction | Terrence Clemens Apitz | — | (714) 264 0766 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| Apk Development INC | Joe Yong Kim | — | (714) 249 3263 | GC, remodel, ADU | Yorba Linda · Orange County | — | — |
| Aplin Masonry Designs INC | Robert John Aplin | — | (714) 887 7486 | Other | Huntington Beach · Orange County | — | — |
| Aplus Development | Victor Tang | — | (949) 278 6682 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Apollo Electric | Richard Kelly Shay | chrischatzis@gmail.com | (801) 554-3344 | Electricians | Brea · Orange County | — | — |
| Apollo Mechanical Solutions LLC | James Anthony Italiano | — | (208) 860 4863 | HVAC | Mission Viejo · Orange County | — | — |
| Apollotek International INC | Jeff Hatamkhani | — | (949) 833 0028 | Other | Irvine · Orange County | — | — |
| Apple Lock & Safe | Apple Lock & Safe | — | (714) 309 8533 | Other | Fullerton · Orange County | — | — |
| Apple Sign & Graphics | Apple Sign & Graphics | — | (714) 894 1126 | Other | Garden Grove · Orange County | — | — |
| Appliance Installation | Juan Carlos Moreno Nieto | — | (714) 253 9515 | Other | Anaheim · Orange County | — | — |
| Applied Air Conditioning INC | Rudy Portillo | — | (714) 545 1917 | HVAC | Fullerton · Orange County | — | — |
| Applied Air Conditioning INC DBA Applied Air | Carmen Tamara Koo-Hernandez | — | (714) 545 1917 | HVAC | Fullerton · Orange County | — | — |
| Applied Geokinetics LP | Glenn David Tofani | — | (949) 502 5353 | Electricians | Irvine · Orange County | — | — |
| Applied Integrated Solutions INC | Sonia Valentin Barrios | — | (949) 855 2255 | Other | Mission Viejo · Orange County | — | — |
| Applied Pavement Applications | Applied Pavement Applications | — | (714) 305 0743 | Other | Yorba Linda · Orange County | — | — |
| Applied Plastering INC | Brian Scott Jr Garcia | — | (657) 218 1061 | Other | Rancho Santa Margarita · Orange County | — | — |
| Applied Plumbing And Rooter INC | Vincent Michael Alker | — | (714) 215 8007 | Other | Rancho Santa Margarita · Orange County | — | — |
| Applied Roofing Services | Jeffrey Adam| Cardenas Jeff Adam Cardenas | — | (800) 895 9589 | Other roofers | Orange · Orange County | — | — |
| Applied Vinyl Tech INC | Troy Lance Harris | — | (949) 650 1969 | Pool | Newport Beach · Orange County | — | — |
| Applied Wall Systems | Christopher Michael Gillaspy | — | (949) 244 7965 | GC, remodel, ADU | Orange · Orange County | — | — |
| Appro Electric INC | Jonghwa Won | — | (714) 305 4101 | Electricians | Orange · Orange County | — | — |
| Approved Property Services | Pineda Miguel Solis | approvedpservices@gmail.com | (714) 222 7059 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| Apsi Construction Management | Atul Ashok Apte | — | (949) 679 0202 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Apt Painting INC | Kyle Kenneth Apt | — | (714) 365 7421 | Windows, patio, painters | Yorba Linda · Orange County | — | — |
| Apu General Construction INC | Yury Edgar Leon | yury@apugeneralconstruction.com | (714) 609 4002 | GC, remodel, ADU | Garden Grove · Orange County | — | — |
| Apx Builders LLC | Stuart Dean Lockhar Campbell | — | (808) 464 2348 | GC, remodel, ADU | San Clemente · Orange County | — | — |
| Aqe Restoration Construction | Daniel Thomas Maas | — | (714) 444 1851 | Restoration | Lake Forest · Orange County | — | — |
| Aqua Pacific Pool Service & Repair INC | Jeffrey Michael Mckahan | — | (714) 497 5055 | Pool | Irvine · Orange County | — | — |
| Aqua Performance Plumbing INC | Robert Michael Buroza | — | (949) 289 0185 | Electricians | Capistrano Beach · Orange County | — | — |
| Aqua Pool Pros INC | Saavedra Jesus Torres | — | (800) 836 5303 | Pool | Orange · Orange County | — | — |
| Aqua Pure Pool & Spa Service | Steven David Kile | — | (714) 390 6924 | Pool | Fullerton · Orange County | — | — |
| Aqua Scapes Pools & Spas INC | Gordon Kent Sipes | — | (949) 448 7665 | Pool | San Clemente · Orange County | — | — |
| Aqua Star Pool And Spa Service & Repair | Christopher Patrick Dienst | — | (949) 395 7942 | Pool | Trabuco Canyon · Orange County | — | — |
| Aqua System Pools Service | Robert Allen Fritsche | — | (949) 933 7695 | Pool | Newport Beach · Orange County | — | — |
| Aqua Wright Pool Maintenance Repair | Aqua Wright Pool Maintenance Repair | — | (714) 612 7821 | Pool | Huntington Beach · Orange County | — | — |
| Aqua-tech | Fogarty Ronald | — | (949) 489 0273 | Windows, patio, painters | Laguna Niguel · Orange County | — | — |
| Aqua-tek Pool Services | Kristen Hilmar Heftved | — | (714) 241 1315 | Pool | Santa Ana · Orange County | — | — |
| Aquacare Pool Services INC | Matthew Thomas Wright | — | (949) 239 7665 | Pool | Foothill Ranch · Orange County | — | — |