| Mulholland Electric | B + C10 | 2014 | Renew by Dec 31, 2026 |
| Mullins General Construction & Fine Painting | B + C33 | 2014 | Active |
| MW Success Construction Inc | B + C10, C36 | 2026 | Active |
| Mwangi Engineering Inc | A | 2023 | Active |
| N A S Group | B | 2007 | Active |
| N B C Construction & Engineering Inc | A, B | 2005 | Active |
| N C P General Contracting Inc | B | 2020 | Active |
| N E Stone Corp | B | 2018 | Active |
| N T K Construction Inc | A, B + C31, C36, HAZ | 2004 | Renew by Dec 31, 2026 |
| Nabi Construction | B + C8 | 2001 | Active |
| Nancy Built LLC | B | 2010 | Active |
| Nash Builders Inc | B | 2007 | Active |
| Nation Fidelity Construction Inc | B | 1991 | Active |
| Nazca Management Inc | B | 2010 | Active |
| Nbay Construction & Remodeling Inc | B | 2019 | Active |
| Neeve Engineering Inc | A | 2018 | Renew by Dec 31, 2026 |
| Nelson Contracting Inc | B | 2007 | Active |
| Nelson Ronald R Contractor Inc | A + C8 | 1967 | Active |
| Neng Construction Inc | B + C36 | 2018 | Active |
| Neng Plumbing Inc | B + C36 | 2022 | Active |
| Nerland Building And Restoration Inc | B | 2002 | Active |
| New Force Construction | B | 2023 | Active |
| New Ihome Construction Inc | B | 2022 | Active |
| New Marble Group Inc | B + C54 | 2019 | Active |
| New Star Construction Inc | B | 2002 | Active |
| Newly Renovated Inc | B | 2024 | Active |
| Newman General Construction Inc | B + C33 | 2013 | Active |
| Nexa Build Inc | B | 2024 | Active |
| Ng's Electrical Inc | B + C10 | 2019 | Active |
| Ng's Landmark Building & Engineering Contractors Inc | A, B | 1988 | Renew by Nov 30, 2026 |
| Nibbi Bros Associates Inc | A, B + C8 | 1998 | Renew by Dec 31, 2026 |
| Nibbi Bros Inc | A, B + ASB | 1965 | Renew by Nov 30, 2026 |
| Nibbi Concrete | A, B + C8 | 2005 | Active |
| Nibbi SPS | A, B | 2020 | Renew by Nov 30, 2026 |
| Nibbi-Marinship JV | A, B + C8, C31 | 2026 | Active |
| Nibbi-Pilot JV | A, B | 2025 | Active |
| NK Construction And Real Estate Development LLC | B | 2024 | Active |
| Nob Hill Construction Inc | B | 2016 | Active |
| Norcal Adu Builders LLC | B | 2023 | Active |
| North Bay Construction LLC | B | 2007 | Active |
| North Coast Electric And Construction Inc | B + C10 | 2006 | Active |
| North Gate Builders Inc | B | 2001 | Active |
| North Point Construction Inc | B | 1991 | Active |
| Northside Engineering Inc | A | 2004 | Active |
| Northwest Demolition Inc | A, B + HAZ | 1989 | Active |
| O C A L Builders Inc | B | 2006 | Active |
| O Donoghue Construction Inc | B | 2008 | Active |
| O'Connor Pipelines Inc | A | 2019 | Active |
| O'Kane Construction LLC | B | 1995 | Active |
| O'Keeffe Construction Inc | B | 2000 | Renew by Dec 31, 2026 |
| O'Keeffe Mechanical Co Inc | B + C4, C10, C20 +4 | 1994 | Active |
| O'Neill Buck Builders Inc | B | 2006 | Active |
| O'Reilly Sean General Contractor Inc | B | 2002 | Active |
| O'Shaughnessy Michael Construction Inc | A + C31 | 2013 | Active |
| O'Shea Co Home Grown Construction LLC | B | 2007 | Active |
| Oarcon Inc | B | 2016 | Active |
| Occidental Power Solar & Cogen | B + C10, C46 | 1990 | Active |
| Oceanside Sheetmetal Inc | B + C20, C36, C43 | 2011 | Active |
| Oconaire Construction Inc | B | 2015 | Active |
| Olcote Builders Inc | B | 2025 | Active |
| Old Sod Construction Inc | B + C8 | 1999 | Active |
| Olive Construction Inc | B | 2009 | Active |
| Olive's Construction LLC | B | 2025 | Active |
| Oliver Mackin Construction | B | 2013 | Active |
| Olmec Builders Inc | B | 2019 | Active |
| Oltranti Construction Company Inc | B | 1988 | Active |
| On Tung Inc | B | 2015 | Active |
| One Construction General Builders Inc | B | 2025 | Active |
| One Hat One Hand LLC | B | 2019 | Active |
| Only Kitchens And Baths Inc | B + D34 | 2022 | Active |
| Orchard Construction Inc | B | 2017 | Active |
| Orebend Bldrs Inc | B + C4, C36, C60 | 2016 | Active |
| Ovisco Inc | B + C36 | 1986 | Active |
| P 3 Construction & Remodeling Inc | B | 2011 | Active |
| P F Construction Co | B + C36 | 1989 | Active |
| P J M Construction LLC | B | 2004 | Active |
| P O A S Construction Inc | B | 2010 | Active |
| P&P Construction Services Inc | B | 2013 | Active |
| Pacheco Builders Inc | B | 2009 | Active |
| Pacific Automatic Sprinkler Co | B + C16 | 1971 | Active |
| Pacific Construction | B | 2023 | Active |
| Pacific Contracting | B | 1993 | Active |
| Pacific Engineering & Construction Inc | A, B + ASB, HAZ | 2005 | Active |
| Pacific Gateway Builders Inc | B | 2010 | Active |
| Pacific Green Construction Inc | B + C33 | 2007 | Active |
| Pacific International Engineering | A, B | 2023 | Active |
| Pacific Pars Construction LLC | A, B | 2023 | Active |
| Pacific Structures Inc | B + C8 | 2008 | Renew by Dec 31, 2026 |
| Paniagua Construction Inc | B | 1996 | Active |
| Pantheon Construction Management Inc | B | 2003 | Active |
| Paramount Builders & Management Inc | A, B | 2025 | Active |
| Parkin Inc | A, B | 2012 | Active |
| Parkson Construction Company | A, B + C36 | 2018 | Active |
| Pattani Construction Company | B | 1994 | Active |
| Paul O'Driscoll Inc | B | 2005 | Active |
| Pca Consulting Group Inc | A, B | 1992 | Active |
| Peak General Contractors Inc | B | 2005 | Active |
| Perez Construction LLC | B | 2017 | Active |
| Phase2 Builders Inc | B | 2009 | Active |
| Phoenix Electric Company | A + C10 | 2002 | Active |