| 3 Eleven Doors & Gates INC | Juan M Fernandez Diaz | — | (818) 913 5961 | Other | Arleta · Los Angeles County | — | — |
| 3 Feathers Construction | Ronald Frederick Ii Montez | — | (702) 339 2964 | GC, remodel, ADU | Loomis · Placer County | — | — |
| 3 Fingers Painting INC | Sopheap Phang | — | (646) 407 2131 | Windows, patio, painters | San Francisco · San Francisco County | — | — |
| 3 Forks Construction | Chad Lee Gardner | — | (916) 295 3690 | GC, remodel, ADU | Lincoln · Placer County | — | — |
| 3 G Engineering LLC | Mitchell Flint Brown | — | (559) 741 3837 | Other | Visalia · Tulare County | — | — |
| 3 Generations Improvements INC | Kurt Robert Owens | — | (916) 932 2315 | Windows, patio, painters | Folsom · Sacramento County | — | — |
| 3 High Painting Co | Hong Jun Kim | — | (714) 530 4889 | Windows, patio, painters | Tustin · Orange County | — | — |
| 3 In 0ne Landscape | 3 In 0ne Landscape | — | (530) 514 7124 | Windows, patio, painters | Chico · Butte County | — | — |
| 3 In 1 Bathtub And Kitchen Refinishing INC | Estrada Heriberto | — | (619) 575 9253 | Other | Chula Vista · San Diego County | — | — |
| 3 J Construction | Rodelio Quizon Santos | — | (562) 406 2292 | GC, remodel, ADU | Norwalk · Los Angeles County | — | — |
| 3 J Electrical | Junling Zeng | — | (415) 568 0719 | Electricians | Pacifica · San Mateo County | — | — |
| 3 Kings Associates INC | Zipporah Maria Patton | — | (310) 215 9940 | GC, remodel, ADU | Los Angeles · Los Angeles County | — | — |
| 3 Kings Builders LLC | Mark Andrew Reyes | mail@kings-builders.com | (415) 713 6223 | GC, remodel, ADU | Napa · Napa County | — | — |
| 3 L's Builders INC | Luis Alonso Santiago Sanchez | — | (805) 868 3594 | GC, remodel, ADU | Santa Maria · Santa Barbara County | — | — |
| 3 Lopez Brother's Construction Corp | Alejandro Gomez | — | (442) 245 9705 | GC, remodel, ADU | San Marcos · San Diego County | — | — |
| 3 M Electric | Mariano Amio Ocampo | shea@m-electric.com | (858) 357 1126 | Electricians | Escondido · San Diego County | — | — |
| 3 Mountain Construction | James Harold Huss | glenng@mountain-construction.com | (913) 207-5937 | GC, remodel, ADU | Lincoln · Placer County | — | — |
| 3 N 1 Construction INC | Mak Ka Wang | info@nconstruction.com | (415) 310 8878 | GC, remodel, ADU | South San Francisco · San Mateo County | — | — |
| 3 N 1 Electric INC | Jose Luis Naranjo | — | (909) 562 0864 | Electricians | Chino · San Bernardino County | — | — |
| 3 N 1 Landscape | 3 N 1 Landscape | — | (760) 851 4972 | Windows, patio, painters | Thousand Palms · Riverside County | — | — |
| 3 Palms Pool And Spa | 3 Palms Pool And Spa | — | (951) 722 6002 | Pool | Moreno Valley · Riverside County | — | — |
| 3 Peaks Construction LLC | Christopher Michael Rice | guy@infinitydesignbuild.com | (760) 212 5484 | GC, remodel, ADU | Carlsbad · San Diego County | — | — |
| 3 Phase Electric Co | Corral Orlando | kent@phaseelectric.com | (214) 808-1003 | Electricians | Whittier · Los Angeles County | — | — |
| 3 Phase Electric Co | Malin Ansara Wright | kent@phaseelectric.com | (214) 808-1003 | Electricians | Lancaster · Los Angeles County | — | — |
| 3 Phaze Electric | Thomas Oc | — | (408) 591 5545 | Electricians | Manteca · San Joaquin County | — | — |
| 3 Pinos INC | Bartolo Lopez | — | (818) 349 8226 | Windows, patio, painters | Northridge · Los Angeles County | — | — |
| 3 Power Electric INC | Alen Naun Rodriguez Flores | info@powerelectric.com | (650) 759 0043 | Electricians | Daly City · San Mateo County | — | — |
| 3 Pyramid Construction & Renovation Corporation | Attila Kollar | — | (916) 544 8114 | GC, remodel, ADU | Sacramento · Sacramento County | — | — |
| 3 R Construction | Timothy Dean Chansler | — | (559) 303 0587 | GC, remodel, ADU | Three Rivers · Tulare County | — | — |
| 3 R Electric | Reynold Robby Ramirez | — | (831) 229 0760 | Electricians | Prunedale · Monterey County | — | — |
| 3 Rivers Landscaping | Larry Joseph Jr Ruelas | — | (916) 803 7787 | Windows, patio, painters | Sacramento · Sacramento County | — | — |
| 3 S Network INC | Gholam Hossein Taghipoor | — | (949) 916 4561 | GC, remodel, ADU | Tustin · Orange County | — | — |
| 3 Sands Handyman LLC DBA Flora Scott Construction | Scott David Flora | — | (661) 317 6300 | GC, remodel, ADU | Palmdale · Los Angeles County | — | — |
| 3 Seven 10 Enterprise | 3 Seven 10 Enterprise | — | (818) 336 7336 | Electricians | Glendora · Los Angeles County | — | — |
| 3 Sixty-five Framers | Cordero Jose Alfredo Blanco | — | (951) 642 1999 | Other | Perris · Riverside County | — | — |
| 3 Sons Garage Doors INC | Jeffrey Lawrence Frazier | — | (559) 360 4818 | Other | Clovis · Fresno County | — | — |
| 3 Sons Plumbing INC | Joel Mark Levine | — | (760) 567 1570 | Other | La Quinta · Riverside County | — | — |
| 3 Star Construction INC | Erick Guzman Vasquez | — | (408) 334 8675 | GC, remodel, ADU | San Jose · Santa Clara County | — | — |
| 3 Strikes Construction INC | Patrick Francis Roberts | — | (559) 307 0819 | GC, remodel, ADU | Fresno · Fresno County | — | — |
| 3 T Media INC | Joseph Dizor Tolentino | — | (714) 227 6057 | Other | Diamond Bar · Los Angeles County | — | — |