| Nieporte Roofing | Paul Dustin Bancroft | — | (310) 595 4311 | Other roofers | Arroyo Grande · San Luis Obispo County | — | — |
| Nieporte Roofing INC | Jonathan Charles Nieporte | — | (805) 547 0100 | Other roofers | San Luis Obispo · San Luis Obispo County | — | — |
| Nissan Charging Station | Nissan Charging Station | — | (877) 664-2738 | EV chargers | San Luis Obispo · San Luis Obispo County | — | — |
| Nixon's Quality Construction | Steve Michael Nixon | — | (661) 578 7915 | GC, remodel, ADU | Arroyo Grande · San Luis Obispo County | — | — |
| Noel's Plumbing | Noel's Plumbing | — | (805) 674 2734 | Other | Paso Robles · San Luis Obispo County | — | — |
| Noni Granite And Stone | Noni Granite And Stone | — | (805) 907 9297 | Other | Paso Robles · San Luis Obispo County | — | — |
| Nordic Builders & Associates INC | Jimmy Bert Randeen | — | (805) 528 5902 | GC, remodel, ADU | Morro Bay · San Luis Obispo County | — | — |
| North Coast Tree Service | Tim Michael Radecki | — | (805) 927 8525 | Tree | Cambria · San Luis Obispo County | — | — |
| North County Asphalt | North County Asphalt | — | (805) 466 7325 | Other | Atascadero · San Luis Obispo County | — | — |
| North County Insulation INC | Joel Lee Smallwood | — | (805) 460 0122 | Other | Atascadero · San Luis Obispo County | — | — |
| North County Property Management And Maintenance General Engineer | Joshua Morris Yaguda | — | (805) 635 5960 | Other | Paso Robles · San Luis Obispo County | — | — |
| North County Septic Service INC | Michael James Ban | — | (805) 239 3838 | Other | Paso Robles · San Luis Obispo County | — | — |
| Nufinishpro Synthetic Refinishing | Craig Charles Nunes | — | (805) 399 4488 | Other | San Luis Obispo · San Luis Obispo County | — | — |
| Nunno Corporation Ltd | Raymond Charles Phillips | — | (805) 238 6801 | GC, remodel, ADU | Paso Robles · San Luis Obispo County | — | — |
| O'brien Construction | Charles William| O'brien Bill O'brien | — | (805) 286 8146 | GC, remodel, ADU | Pismo Beach · San Luis Obispo County | — | — |
| O'connor Pest Control Central Coast | O'connor Pest Control Central Coast | — | (805) 330-9247 | Pest, tile roofs | Nipomo · San Luis Obispo County | — | — |
| O'donnell's | Michael Anthony O'donnell | — | (805) 461 5626 | GC, remodel, ADU | Santa Margarita · San Luis Obispo County | — | — |
| O'malley's Plumbing | O'malley's Plumbing | — | (805) 927 2690 | Other | Cayucos · San Luis Obispo County | — | — |
| O'neal Brothers Electric | Michael Evan O'neal | — | (805) 801 1419 | Electricians | Templeton · San Luis Obispo County | — | — |
| Oak Coast Construction INC | Poul Erik Norholm | — | (805) 714 0446 | GC, remodel, ADU | Arroyo Grande · San Luis Obispo County | — | — |
| Oak N'stone Construction | Rylan James Von Bargen | — | (805) 835 3595 | GC, remodel, ADU | Atascadero · San Luis Obispo County | — | — |
| Oak Ridge Custom Builders LLC | Patrick Erinn Jarvis | — | (805) 277 2177 | GC, remodel, ADU | Atascadero · San Luis Obispo County | — | — |
| Oak Springs Partners | Michael Lawrence Schatz | — | (805) 844 5713 | GC, remodel, ADU | Pismo Beach · San Luis Obispo County | — | — |
| Oak Wood Construction | Jose Reuben Garcia | — | (805) 423 4981 | GC, remodel, ADU | Paso Robles · San Luis Obispo County | — | — |
| Obispo Electric | Robert William Garrison | — | (805) 610 5185 | Electricians | San Luis Obispo · San Luis Obispo County | — | — |
| Obispo Tile INC | Cynthia Denise Cochran | anapbm@gmail.com | (805) 441 7124 | Other | Paso Robles · San Luis Obispo County | — | — |
| Oc3 Construction & Consulting INC | Keith Allen Oconnor | — | (805) 550 6290 | GC, remodel, ADU | San Miguel · San Luis Obispo County | — | — |
| Ocean Air INC | Chris Anthony Lopez | — | (805) 473 0413 | HVAC | Grover Beach · San Luis Obispo County | — | — |
| Ocean View Construction | Ruben Phillip Herdt | — | (805) 235 6880 | GC, remodel, ADU | Arroyo Grande · San Luis Obispo County | — | — |
| Ocean View Landscape Designs Inc. | Jeremiah Javier Alvarez | — | (805) 888 1194 | Windows, patio, painters | Oceano · San Luis Obispo County | — | — |
| Ocean View Landscaping | Ocean View Landscaping | — | (805) 266 9292 | Windows, patio, painters | Pismo Beach · San Luis Obispo County | — | — |
| Oceanovac INC | Roger Carson Later | — | (310) 386 1239 | GC, remodel, ADU | Arroyo Grande · San Luis Obispo County | — | — |
| Odenwald Construction | Odenwald Construction | — | (805) 927 5537 | GC, remodel, ADU | Cambria · San Luis Obispo County | — | — |
| Odenwald Construction Company INC | Anthony Arthur Odenwald | — | (805) 801 4439 | GC, remodel, ADU | Templeton · San Luis Obispo County | — | — |
| Odenwald Hand Built | Odenwald Taylor | — | (805) 423 5022 | GC, remodel, ADU | Templeton · San Luis Obispo County | — | — |
| Off The Wall Construction INC | Dustin Mathew Graham | — | (805) 710 1360 | GC, remodel, ADU | Pismo Beach · San Luis Obispo County | — | — |
| Off The Wall Custom Flooring | Off The Wall Custom Flooring | — | (805) 835 3993 | Other | Paso Robles · San Luis Obispo County | — | — |
| Olcott Construction | Aaron Joseph Olcott | — | (805) 459 0076 | GC, remodel, ADU | Los Osos · San Luis Obispo County | — | — |
| Old Creek Construction | Scott Cameron Blanchard | — | (805) 748 0083 | GC, remodel, ADU | Cayucos · San Luis Obispo County | — | — |
| Old World Tile | Old World Tile | — | (805) 298 0434 | Other | Los Osos · San Luis Obispo County | — | — |