| Will Delfino | Will Delfino | — | (805) 358 4310 | Electricians | Camarillo · Ventura County | — | — |
| William A Fairfield Ii | William A Fairfield Ii | — | (707) 396 1621 | GC, remodel, ADU | Hidden Valley · Ventura County | — | — |
| William Arthur | William Arthur | — | (310) 339 1601 | Other | Oxnard · Ventura County | — | — |
| William Christopher Quilter | William Christopher Quilter | — | (805) 428 3707 | GC, remodel, ADU | Thousand Oaks · Ventura County | — | — |
| William Clayton Construction | William James Clayton | — | (805) 708 2455 | GC, remodel, ADU | Ventura · Ventura County | — | — |
| William Craig Davis Jr | William Craig Davis Jr | — | (818) 621 6329 | Windows, patio, painters | Camarillo · Ventura County | — | — |
| William Dean's Plumbing | William Dean's Plumbing | — | (805) 216 9637 | Other | Ventura · Ventura County | — | — |
| William Elkins Construction INC | William Stanley Ii Elkins | — | (805) 200 7914 | GC, remodel, ADU | Ventura · Ventura County | — | — |
| William Fairbanks Jr | William Fairbanks Jr | — | (818) 735 7311 | GC, remodel, ADU | Westlake Village · Ventura County | — | — |
| William G Zatorski | William G Zatorski | — | (818) 687 4489 | Windows, patio, painters | Camarillo · Ventura County | — | — |
| William Gavin General Contractor | William Gavin General Contractor | — | (805) 290 2964 | GC, remodel, ADU | Ventura · Ventura County | — | — |
| William Herbert Davis | William Herbert Davis | — | (805) 279 7771 | GC, remodel, ADU | Simi Valley · Ventura County | — | — |
| William Howard Construction INC | William Clark Howard | — | (805) 654 1971 | GC, remodel, ADU | Ventura · Ventura County | — | — |
| William J Norris | William J Norris | — | (805) 409 5763 | Electricians | Moorpark · Ventura County | — | — |
| William Jay Murdock | William Jay Murdock | — | (805) 642 9384 | Other | Ventura · Ventura County | — | — |
| William John Haddad | William John Haddad | — | (818) 515 2877 | Other | Simi Valley · Ventura County | — | — |
| William Jorge Amador | William Jorge Amador | — | (805) 558 4330 | GC, remodel, ADU | Westlake Village · Ventura County | — | — |
| William Michael Hughes DBA B & M Mobile Electronics | B & M Mobile Electronics | — | (818) 899 1222 | Other | Simi Valley · Ventura County | — | — |
| William Reyes Lighting INC | Stuart William Sulpizio | — | (818) 749 4620 | Electricians | Simi Valley · Ventura County | — | — |
| William Ulrich Construction | William Allen Ulrich | — | (805) 657 5566 | GC, remodel, ADU | Ojai · Ventura County | — | — |
| William Wilson Construction & Development | William Francis Wilson | — | (805) 390 4504 | GC, remodel, ADU | Thousand Oaks · Ventura County | — | — |
| William Wise Painting And Decorating | William Wise Painting And Decorating | — | (818) 383 3342 | Windows, patio, painters | Westlake Village · Ventura County | — | — |
| Williams Construction | Mike Dennis Williams | — | (805) 402 0647 | GC, remodel, ADU | Newbury Park · Ventura County | — | — |
| Williams Custom Security | Donald Clayton Williams | — | (818) 974 0020 | Electricians | Simi Valley · Ventura County | — | — |
| Williamson Construction | Robert Sam Williamson | — | (805) 320 5152 | GC, remodel, ADU | Ventura · Ventura County | — | — |
| Wills Custom Painting | Wills Custom Painting | buzwills@yahoo.com | (805) 797 3973 | Windows, patio, painters | Ventura · Ventura County | — | — |
| Wilshire Media Systems INC | Michael Robert Mc Master | — | (805) 497 1179 | Other | Westlake Village · Ventura County | — | — |
| Window Design Group | Cindy Hem Patai | leads@windowdesigngroup.com | (805) 426 3584 | Windows, patio, painters | Thousand Oaks · Ventura County | — | — |
| Windows At Affordable Prices | Windows At Affordable Prices | — | (805) 657 5993 | Windows, patio, painters | Simi Valley · Ventura County | — | — |
| Windsor Builders INC | Pentti Lehtonen | — | (805) 815 7667 | GC, remodel, ADU | Thousand Oaks · Ventura County | — | — |
| Wingate Earthworks INC | Nicholas William Wingate | doughigson@gmail.com | (805) 798 5488 | Other | Ojai · Ventura County | — | — |
| Wired | James Patrick Reilly | — | (805) 987 0995 | Electricians | Camarillo · Ventura County | — | — |
| Wired City Electric | Vincent James Knupp | — | (818) 486 6963 | Electricians | Thousand Oaks · Ventura County | — | — |
| Wirelessguys INC | Steven Andrew Williams | — | (805) 501 8547 | GC, remodel, ADU | Moorpark · Ventura County | — | — |
| Wise One Plumbing INC | Jerry Robert Wise | — | (323) 509 6129 | Other | Simi Valley · Ventura County | — | — |
| Wisegarver Construction | Wade Mead Wisegarver | — | (805) 760 4029 | GC, remodel, ADU | Ventura · Ventura County | — | — |
| Wisneski Painting INC | Kirk Lee Wisneski | — | (805) 340 9897 | Windows, patio, painters | Thousand Oaks · Ventura County | — | — |
| With The Grain Builders LLC | Douglas Allen Wood | — | (805) 798 4486 | GC, remodel, ADU | Ventura · Ventura County | — | — |
| Witt Randy Construction INC | Randall Alan Witt | — | (805) 551 7236 | Electricians | Newbury Park · Ventura County | — | — |
| Wl Plumbing | Wl Plumbing | — | (213) 268 5366 | Other | Thousand Oaks · Ventura County | — | — |