| Juan Franco Construction | Juan Jr Franco | — | (209) 603 6164 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| Juan Gutierrez Construction | Juan Manuel Gutierrez | — | (209) 818 6460 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| Juan Reyes | Juan Reyes | — | (925) 216 0354 | Other | Lathrop · San Joaquin County | — | — |
| Juan Vazquez Landscape | Juan Vazquez Landscape | — | (209) 321 6392 | Windows, patio, painters | Tracy · San Joaquin County | — | — |
| Juju Flooring INC | Julian Ricardo Ponce | jujuflooring@gmail.com | (209) 670 4038 | Other | Stockton · San Joaquin County | — | — |
| Juma Construction | Madrigal Magana Juan | — | (209) 456 4678 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| Jump Construction INC | Stephen Andrew Jump | — | (209) 649 7077 | GC, remodel, ADU | Lodi · San Joaquin County | — | — |
| Justified Technology Integrators | David Alan Joseph Cuslidge | — | (919) 455 0527 | Other | Stockton · San Joaquin County | — | — |
| Justin Barth Fencing | Justin Barth Fencing | — | (209) 993 7599 | Other | Lodi · San Joaquin County | — | — |
| Justin Cracraft Backhoe Services INC | Justin Lee Cracraft | — | (209) 640 8310 | Other | Tracy · San Joaquin County | — | — |
| Justin L Ordonez | Justin L Ordonez | — | (209) 479 1128 | HVAC | Tracy · San Joaquin County | — | — |
| Justin Sauceda Construction INC | Justin Brice Sauceda | — | (209) 640 1831 | GC, remodel, ADU | Lathrop · San Joaquin County | — | — |
| Jv Drywall | Jv Drywall | impallari@gmail.com | (209) 225 7229 | Other | Stockton · San Joaquin County | — | — |
| Jv Green View INC | Jose Luis Vega Zavala | — | (408) 218 6344 | Windows, patio, painters | Tracy · San Joaquin County | — | — |
| Jv Lath & Plastering | Jv Lath & Plastering | — | (209) 319 7500 | Other | Stockton · San Joaquin County | — | — |
| Jv Quality Construction | Vazquez Garcia Jesus | — | (209) 923 5062 | GC, remodel, ADU | Manteca · San Joaquin County | — | — |
| Jvl Flooring | Jvl Flooring | — | (209) 663 5620 | Other | Lodi · San Joaquin County | — | — |
| Jvm Builders INC | Larry Liang-Yao Wang | — | (209) 431 7603 | GC, remodel, ADU | Lathrop · San Joaquin County | — | — |
| Jvn Landscapes INC | James Robert Van Nieuwenhuyzen | — | (209) 480 4358 | Windows, patio, painters | Ripon · San Joaquin County | — | — |
| Jvs Plumbing & Rooter | Jvs Plumbing & Rooter | — | (209) 229 5487 | Other | Lathrop · San Joaquin County | — | — |
| Jym Construction INC | Jose Edgar Ramirez-Bonilla | — | (209) 328 5642 | GC, remodel, ADU | Manteca · San Joaquin County | — | — |
| K & D Environmental | K & D Environmental | — | (209) 824 2864 | Other | Manteca · San Joaquin County | — | — |
| K & M Final Phase Cleaning INC | Craig Anthony Fullard | — | (209) 229 1129 | Other | Tracy · San Joaquin County | — | — |
| K & S Ironworks INC | Hernandez Nohemi Avelino | — | (510) 325 4857 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| K B C Construction Cleanup Services | Gamaliel Lara | — | (510) 706 9548 | Other roofers | Stockton · San Joaquin County | — | — |
| K Brar Construction | Kevin Singh Brar | — | (209) 481 5402 | GC, remodel, ADU | Manteca · San Joaquin County | — | — |
| K C G Painting INC | Melquicedex Danilo Ceren Padilla | mel@kcgpainting.com | (408) 805 6791 | Windows, patio, painters | Manteca · San Joaquin County | — | — |
| K D S Plumbing | K D S Plumbing | — | (209) 969 2573 | Other | Stockton · San Joaquin County | — | — |
| K L T Electrical Co | Kevin Lloyd Thompson | — | (209) 915 2421 | Electricians | Lathrop · San Joaquin County | — | — |
| K M Tile Corporation | Trujillo Gustavo Ramos | — | (209) 518 7660 | Other | Stockton · San Joaquin County | — | — |
| K N S Flooring | K N S Flooring | — | (209) 329 7664 | Other | Lodi · San Joaquin County | — | — |
| K P I Signs & Graphics | Kenneth Paul Parish | — | (209) 327 4745 | Other | Lodi · San Joaquin County | — | — |
| K&t Landscaping | Thong Thai Nguyen | — | (209) 587 3151 | Windows, patio, painters | Stockton · San Joaquin County | — | — |
| K5 Signs & Graphics INC | Michael Sean Keough | — | (925) 373 0775 | Other | Stockton · San Joaquin County | — | — |
| Ka Concrete Pumping INC | Armando Avila | — | (209) 471 5439 | Other | Lathrop · San Joaquin County | — | — |
| Ka Wai Lau | Ka Wai Lau | — | (510) 282 3364 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| Kaiser Commercial Petroleum | Kaiser Commercial Petroleum | — | (209) 887 2639 | Other | Linden · San Joaquin County | — | — |
| Kaiser's Heating & Air | Kaiser's Heating & Air | — | (209) 403 5331 | HVAC | Stockton · San Joaquin County | — | — |
| Kamper Fabrication INC | Brenda Carole Kamper | — | (209) 599 7137 | Other | Ripon · San Joaquin County | — | — |
| Kamps Propane INC | Michael Patrick Sexton | media@superiorplus.com | (209) 561 8147 | Other | Manteca · San Joaquin County | — | — |