| Contempo Designs INC | Steven Oviedo | — | (714) 865 2110 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| Contemporary Air Control INC | Scott David Mockler | — | (714) 373 5331 | HVAC | Costa Mesa · Orange County | — | — |
| Contemporary Heating & Air Conditioning INC | Randy Harold Peterson | — | (714) 572 8914 | HVAC | Placentia · Orange County | — | — |
| Contemporary Home Builders INC | Petrovic Dragan | — | (949) 922 2047 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Continental Concrete Cutting INC | Shelane Wong Chow | — | (714) 998 5700 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| Continental Design Build INC | Frank Edward Sator | — | (714) 630 6467 | HVAC | Anaheim · Orange County | — | — |
| Continental Electric Systems INC | Troy Christopher Ditt | — | (949) 394 1758 | Electricians | Costa Mesa · Orange County | — | — |
| Continental Interior Services INC | Gary Carmelo Amigliore | gary@cisdemo.net | (714) 693 4655 | GC, remodel, ADU | Anaheim Hills · Orange County | — | — |
| Continental Properties | Continental Properties | — | (949) 306 4729 | GC, remodel, ADU | Laguna Beach · Orange County | — | — |
| Continental Property Services INC | Richard Frederick Thies | — | (949) 756 2073 | GC, remodel, ADU | Newport Beach · Orange County | — | — |
| Continental Signs INC | Antonio Garcia | — | (714) 894 2011 | Other | Stanton · Orange County | — | — |
| Contorelli Construction INC | Robert Anthony Contorelli | — | (949) 290 4630 | Electricians | Huntington Beach · Orange County | — | — |
| Contorelli Development | Contorelli Development | — | (949) 444 2653 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| Contorelli Electric | Robert Anthony Contorelli | — | (949) 290 4630 | Electricians | Huntington Beach · Orange County | — | — |
| Contract Carpet Corp | James Keith Auman | — | (714) 888 3200 | Other | Anaheim · Orange County | — | — |
| Contract Installations INC | Christopher Paul Majcherek | — | (714) 685 9136 | Other | Orange · Orange County | — | — |
| Contract Services Group INC | John Kelsey Pearce | — | (714) 582 1807 | GC, remodel, ADU | Brea · Orange County | — | — |
| Contractor 4 Repairs | Contractor 4 Repairs | — | (949) 331 7856 | Electricians | Orange · Orange County | — | — |
| Contractor Orange County INC | Gary Wayne Cuccia | — | (949) 648 0571 | GC, remodel, ADU | San Juan Capistrano · Orange County | — | — |
| Contractor Rojas Roofing INC | Valencia Salvador Rojas | — | (714) 914 6371 | Other roofers | Santa Ana · Orange County | — | — |
| Contractors Door Supply Co INC | Kyle Lindsay Phillips | — | (714) 901 8585 | Other | San Clemente · Orange County | — | — |
| Contreras Power Stucco Masters | Abram Contreras | — | (714) 501 6422 | Other | Placentia · Orange County | — | — |
| Contrex INC | Robin Mark Tulleners | — | (714) 420 1806 | GC, remodel, ADU | Laguna Niguel · Orange County | — | — |
| Control Air Enterprises LLC | Gregory Scott Ellis | — | (714) 777 8600 | HVAC | Anaheim · Orange County | — | — |
| Control Engineering INC | Carlos Herney Carrillo | — | (714) 535 5590 | Electricians | Huntington Beach · Orange County | — | — |
| Control Freaks | Jonathan Sinclair Faulds | — | (714) 366 9792 | Other | Trabuco Canyon · Orange County | — | — |
| Control Freaks LLC | Jonathan Sinclair Faulds | — | (949) 346 1984 | Other | Trabuco Canyon · Orange County | — | — |
| Control System Services | Rick Alan Du Beau | — | (714) 692 8074 | Electricians | Anaheim Hills · Orange County | — | — |
| Controlfs LLC | John James Colligan | — | (657) 232 1231 | Other | Brea · Orange County | — | — |
| Controlled Climates INC | Kevin Michael Vieson | — | (949) 388 8428 | HVAC | Laguna Hills · Orange County | — | — |
| Controlled Environments Construction INC | James Patrick Mc Namara | — | (714) 566 9090 | HVAC | Tustin · Orange County | — | — |
| Controlled Fusion INC | Jeffry Paul-Duane Johnson | — | (818) 422 7700 | Other | Coto De Caza · Orange County | — | — |
| Controlled Key Systems INC | Paul Richard Wojdynski | — | (949) 756 1121 | Other | Irvine · Orange County | — | — |
| Convenient Air INC | Velasquez Tommy | — | (562) 665 5193 | HVAC | La Habra · Orange County | — | — |
| Convention Technical Services INC | Michael Lynn Hust | — | (714) 630 7777 | Electricians | Anaheim · Orange County | — | — |
| Convergint Technologies LLC | Michael Robert Mathes | — | (714) 546 2780 | Electricians | La Palma · Orange County | — | — |
| Converse Enterprises INC | Jack Morgan Ii Converse | — | (714) 331 5017 | Windows, patio, painters | Brea · Orange County | — | — |
| Convert Temp H V A C Mechnical Service | Azpeitia Pedro | — | (714) 318 1711 | HVAC | Buena Park · Orange County | — | — |
| Cook Development Group INC | Dean Adam Cook | — | (714) 504 5295 | GC, remodel, ADU | Costa Mesa · Orange County | — | — |
| Cook Quality Construction INC | Kevin Alan Cook | — | (714) 815 6562 | GC, remodel, ADU | Anaheim · Orange County | — | — |