| Commercial Construction Services INC | Daniel Tyrone Goodman | — | (714) 337 7843 | GC, remodel, ADU | Yorba Linda · Orange County | — | — |
| Commercial Construction Solutions INC | Helga Avila Currier | — | (714) 936 4669 | GC, remodel, ADU | Orange · Orange County | — | — |
| Commercial Custom Seating And Upholstery INC | Jason Benjamin Hood | — | (714) 850 0520 | Other | Garden Grove · Orange County | — | — |
| Commercial Door Company INC | Kristin Kay Slyker | — | (909) 622 6400 | Other | Irvine · Orange County | — | — |
| Commercial Doors | Commercial Doors | — | (714) 396 5858 | Other | Yorba Linda · Orange County | — | — |
| Commercial Electric Systems INC | Charles Samuel Manuel | — | (626) 839 7811 | Electricians | Irvine · Orange County | — | — |
| Commercial Fire Protection LLC | David Blake Edwards | — | (888) 308 3473 | Electricians | Newport Beach · Orange County | — | — |
| Commercial Flooring Installations | Charles Curtis Estrada | — | (714) 528 5100 | Other | Anaheim · Orange County | — | — |
| Commercial Interior Resources | Kenneth Daniel Hurd | — | (949) 752 1470 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Commercial Lock & Security Systems | Charles Edward Brown | — | (714) 633 1499 | Electricians | Orange · Orange County | — | — |
| Commercial Pool Corp Corp | Timothy Lynn Smith | — | (714) 321 5108 | Pool | Huntington Beach · Orange County | — | — |
| Commercial Renovation Construction INC | Jeffrey William Dedmon | — | (949) 615 0419 | GC, remodel, ADU | Orange · Orange County | — | — |
| Commercial Roof Management INC | Chad Eric Beveridge | — | (949) 859 9009 | Other roofers | Irvine · Orange County | — | — |
| Commercial Roofing Empire INC | Kevin Alan Ramirez | — | (714) 566 4417 | Other roofers | Garden Grove · Orange County | — | — |
| Common Cents Electric | Ryan Jonathan Hetzel | — | (714) 783 6409 | Electricians | Cypress · Orange County | — | — |
| Communications Plus | Communications Plus | — | (951) 323 9635 | Other | Costa Mesa · Orange County | — | — |
| Communications Technology | Shahab Vakili | — | (949) 770 7840 | Other | Lake Forest · Orange County | — | — |
| Community Action Partnership Of Orange County | Kanielle Maximilian Rouse | — | (714) 897 6670 | GC, remodel, ADU | Garden Grove · Orange County | — | — |
| Community Asset Services INC | Victor Enoc Zesati | — | (949) 355 4833 | Windows, patio, painters | Fullerton · Orange County | — | — |
| Community Care Painting | Brett Neal Grauman | — | (901) 304 8341 | Windows, patio, painters | Irvine · Orange County | — | — |
| Compac Construction | Richard Jun Ho| Park Jun Ho Park | — | (562) 860 4500 | GC, remodel, ADU | Buena Park · Orange County | — | — |
| Compass Contracting & Consulting INC | Kijoo Sung | — | (714) 904 2200 | GC, remodel, ADU | Fullerton · Orange County | — | — |
| Compass Land Advisors INC | Raffaele Suprano | raffaele@compasslandadvisors.com | (949) 339 8918 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Compass Property Management Corporation | Compass Property Management Corporation | — | (949) 429-7717 | Property managers | San Clemente · Orange County | — | — |
| Compass Services | David Brent Fink | — | (714) 202 5711 | Electricians | Orange · Orange County | — | — |
| Compendium International INC | Mohamood Entezar | — | (800) 983 1190 | Electricians | Silverado · Orange County | — | — |
| Competitive Plumbing | Dennis Joe Agius | — | (949) 246 1987 | Other | Coto De Caza · Orange County | — | — |
| Complete Access Solutions Incorporated | Dinh Phuc Ngo | — | (949) 616 8659 | Electricians | Tustin · Orange County | — | — |
| Complete And Total Construction | Richard Jr Montanez | — | (714) 702 9047 | Electricians | Tustin · Orange County | — | — |
| Complete Building Technology Services INC DBA Castle Defense | Craig Charles Johnson | — | (949) 427 5151 | Electricians | Anaheim · Orange County | — | — |
| Complete Heating And Air Conditioning | Complete Heating And Air Conditioning | — | (714) 256 0726 | HVAC | Brea · Orange County | — | — |
| Complete Landscape Service | Edwin Harry| Viseelos Edwin Harry Vise | — | (949) 355 8542 | Windows, patio, painters | San Juan Capistrano · Orange County | — | — |
| Complete Plumbing Solutions | Complete Plumbing Solutions | — | (714) 686 9052 | GC, remodel, ADU | Fullerton · Orange County | — | — |
| Complete Pool Care | Complete Pool Care | — | (714) 514 3231 | Pool | Anaheim Hills · Orange County | — | — |
| Complete Property Services Corporation | Joshua Jack King | — | (661) 566 9500 | GC, remodel, ADU | Aliso Viejo · Orange County | — | — |
| Complete Roofing Services | Paul Randall Barnes | interested@domainmarket.com | (657) 274 8160 | Other roofers | Orange · Orange County | — | — |
| Complete Thermal Services INC | William Leslie Clements | — | (714) 891 2265 | HVAC | Garden Grove · Orange County | — | — |
| Complete Tile Company | Gregory Lee Keith | — | (714) 771 7298 | Other | Orange · Orange County | — | — |
| Complex Construction | Jesse Reynoso | complexhomebuilds@gmail.com | (902) 809-7668 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| Computcable Communications | Computcable Communications | — | (949) 838 7651 | Other | Irvine · Orange County | — | — |