| 2bsavage INC | Todd D Barden | — | (716) 640 2553 | Other | San Clemente · Orange County | — | — |
| 2by4 Construction & Remodeling INC | Amirabbas Anvari | — | (714) 552 0949 | GC, remodel, ADU | Laguna Hills · Orange County | — | — |
| 2E Design & Development | 2E Design & Development | — | (949) 439 8260 | GC, remodel, ADU | Fountain Valley · Orange County | — | — |
| 2vm Socal Construction | Victor Manuel Martinez | 2vmhome@2vmsocalconstruction.com | (562) 355 0602 | GC, remodel, ADU | Los Alamitos · Orange County | — | — |
| 2x4 Renovation & Remodel | Garcia Fernando Diaz | — | (714) 955 3587 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| 3 A Roofing INC | Auscencio Alvarez Alvarez | info@aroofing.com | (714) 785 7378 | Other roofers | Costa Mesa · Orange County | — | — |
| 3 Brothers Construction Services | Abelardo Ivan Valenzuela-Cardenas | interested@domainmarket.com | (949) 510 2834 | GC, remodel, ADU | Lake Forest · Orange County | — | — |
| 3 Brothers Painting Corp | Jose Maria Catalan Tabarez | — | (714) 376 2940 | Windows, patio, painters | Anaheim · Orange County | — | — |
| 3 Brothers Plumbing INC | Gerardo Daniel Zuniga Meza | — | (909) 525 8153 | Other | Anaheim · Orange County | — | — |
| 3 D G R Installations | Donald Gene Jr Ritter | — | (714) 525 4034 | Other | La Habra · Orange County | — | — |
| 3 Day Blinds LLC | Mbo LLC 3db | — | (949) 236 3540 | Other | Irvine · Orange County | — | — |
| 3 High Painting Co | Hong Jun Kim | — | (714) 530 4889 | Windows, patio, painters | Tustin · Orange County | — | — |
| 3 S Network INC | Gholam Hossein Taghipoor | — | (949) 916 4561 | GC, remodel, ADU | Tustin · Orange County | — | — |
| 3-d Construction Services INC | Robert Camargo | — | (714) 488 8700 | GC, remodel, ADU | Orange · Orange County | — | — |
| 3-d Door Company INC | Mark Anthony Picco | — | (714) 625 0311 | Other | Placentia · Orange County | — | — |
| 3-d Tree Services INC | Robert Camargo | — | (714) 844 4896 | Windows, patio, painters | Orange · Orange County | — | — |
| 313 Tec Solutions | 313 Tec Solutions | — | (916) 390 9603 | Other | Seal Beach · Orange County | — | — |
| 32 Dimensions Maintenance INC | Don Dieu Thanh Ly | — | (949) 648 2490 | HVAC | Westminster · Orange County | — | — |
| 320 Grit INC | Brett Tyler Smith | — | (844) 320 4748 | GC, remodel, ADU | Irvine · Orange County | — | — |
| 321 Epoxy Coatings | Walter Alexander Guevara | — | (714) 376 6017 | Other | Tustin · Orange County | — | — |
| 360 Construction Group INC | Russell Heath Cheverton | — | (310) 567 0348 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| 360 Electricity LLC | James Ezra Bauer | — | (949) 847 8876 | Electricians | Lake Forest · Orange County | — | — |
| 3c's Refinishing & Painting | 3c's Refinishing & Painting | — | (714) 366 4159 | Windows, patio, painters | Anaheim · Orange County | — | — |
| 3D Coating And Painting | Israel Rios | — | (714) 727 7799 | Windows, patio, painters | Tustin · Orange County | — | — |
| 3g's Roofing Corp | Luis Enrique Garcia | — | (714) 650 2096 | Other roofers | Santa Ana · Orange County | — | — |
| 3gm Construction | Miranda-duran Gerardo | enquiry@3gmconstruction.com | (949) 813 7620 | GC, remodel, ADU | San Juan Capistrano · Orange County | — | — |
| 3J Company | James Joseph Ongaro | — | (951) 588 7277 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| 3J Construction LLC | Joseph Adel Zaky | impallari@gmail.com | (714) 402 7550 | GC, remodel, ADU | La Habra · Orange County | — | — |
| 3jc Construction INC DBA Oc Flooring | Byung Kil Kim | — | (909) 896 8467 | GC, remodel, ADU | Irvine · Orange County | — | — |
| 3lite Construction INC | Uriel A Rodriguez Silva | — | (714) 200 7530 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| 3M Construction Corporation | Mahmoud Anis Merzi | — | (949) 898 9595 | GC, remodel, ADU | Anaheim · Orange County | — | — |
| 3P Electric | Christian Carl Peterson | — | (760) 889 0388 | Electricians | San Clemente · Orange County | — | — |
| 4 Clover Landscaping | 4 Clover Landscaping | — | (949) 201 8199 | Windows, patio, painters | Trabuco Canyon · Orange County | — | — |
| 4 Pals INC | Gary Knox Powell | — | (714) 375 1227 | Other | Huntington Beach · Orange County | — | — |
| 405 HVAC | Hossein Barekatain | — | (703) 899 0047 | HVAC | Irvine · Orange County | — | — |
| 4:13 Gc Services | Michael Shawn Johnson | — | (714) 450 2367 | GC, remodel, ADU | Orange · Orange County | — | — |
| 4A Landscape | Aldo Alejandro Vara Olivares | — | (949) 394 0356 | Windows, patio, painters | Costa Mesa · Orange County | — | — |
| 4G Brothers LLC | Juan Luis Garcia Solano | — | (949) 200 0552 | Electricians | Fullerton · Orange County | — | — |
| 4G Trenching | Garrido Humberto Olivares | — | (714) 597 5901 | Other | Orange · Orange County | — | — |
| 4U Global Construction | Abdalrahman Abdalhaq | — | (714) 696 2314 | GC, remodel, ADU | Fullerton · Orange County | — | — |