| Ce Elektro AS | Oslo | 2020 |
| Ce Holding AS | Klepp Stasjon | 2018 |
| Ce Pontoppidan AS | Kragerø | 2014 |
| Cebeco Grupe Nuf | Lt-26131 Elektrenu Sav | 2021 |
| Cebeen Invest AS | Vettre | 1988 |
| Ceca SA | Haugesund | 2000 |
| Ceda Consult & Holding AS | Oslo | 2020 |
| Ceecom Ltd | West Sussex Bn5 9Da England | 2010 |
| Cegro Holding AS | Randaberg | 2005 |
| Cej Entreprenør AS | Oslo | 2022 |
| Cekin AS | Oslo | 2019 |
| Cel-Bud Celina Szlek | Oslo | 2007 |
| Celco Murer Og Flisefirma | Dk-9200 Aalborg | 2013 |
| Celeste AS | Hommersåk | 2019 |
| Cellin Byggtjenester AS | Kvaløya | 2018 |
| Cello Håndverk AS | Kragerø | 2023 |
| Cellwood Machinery AB Nuf | 571 32 Nässjö | 2013 |
| Cels AS | Alta | 2022 |
| Celsius Kulde AS | Sagstua | 2004 |
| Cema Eiendom AS | Ankenes | 2008 |
| Cemento Vestfold AS | Horten | 2022 |
| Cenco AS | Kristiansand S | 2016 |
| Cenitech AS | Orkanger | 2011 |
| Centaur Stempa Wlodzimierz Bygningshåndverker | 80-952 Gdansk | 2005 |
| Center Eiendom AS | Kongsvinger | 2004 |
| Centra Ans | Skien | 1991 |
| Centra Bygg AS | Fjell | 2020 |
| Central Telecom AS | Tønsberg | 2024 |
| Centraltecnica Group SRL | It-34015 Muggia (Ts) | 2018 |
| Centrum Bygg Horten AS | Horten | 1992 |
| Centrum Elektriske AS | Oslo | 2013 |
| Centrum Elektro Holding AS | His | 2021 |
| Centrum Glass AS | Nøtterøy | 1989 |
| Centrum Promocji Polonia Sp.Z O.O. | Pl-96100 Skierniewice | 2020 |
| Centrum Rør AS | Solbergmoen | 1986 |
| Centrum Rør AS | Stavanger | 2004 |
| Centrum Techniki Strzeleckiej, Projektowanie, Budowa, Wyposazanie Strzelnic TEBBEX2 Lukasz Bartkowiak Nuf | 65-705 Zielona Gora | 2026 |
| Centrum VVS AS | Arendal | 1990 |
| Ceop Construction Norway Nuf | Es-31591 Corella - Navarra | 2023 |
| Cera Nuf | Rasta | 2010 |
| Ceramic F&S AS | Hafrsfjord | 2026 |
| Ceramics AS | Trondheim | 2011 |
| Cervi AS | Stathelle | 2023 |
| Cervix Norge AS | Oslo | 2021 |
| Cerwonol Norge AS | Sarpsborg | 1990 |
| Cesar Ubilla AS | Oslo | 2019 |
| Ceva AS | Oslo | 2018 |
| Cevada AS | Bærums Verk | 2025 |
| CF Glass & Railing AS | Ytre Enebakk | 2025 |
| CF Svendsen AS | Hemnes | 2018 |
| Cfa Rørleggerbedrift AS | Gjerdrum | 2011 |
| CFS AS | Nesbyen | 2011 |
| CG Entreprenør AS | Oslo | 2025 |
| CG Glass&Fasade AS | Kristiansand S | 2013 |
| CG Investering AS | Mjølkeråen | 2023 |
| CG Jensen | Oslo | 2011 |
| CG Stillas Drift AS | Ytre Arna | 2023 |
| CGB Holding AS | Kristiansand S | 2014 |
| CGH Group SP. Z O.O. | Pl-85-461 Bydgoszcz | 2025 |
| CGT S.P.A. | It-13100 Vercelli | 2012 |
| CH Bygg AS | Kristiansand S | 2019 |
| CH Bygg Tjenester AS | Snåsa | 2023 |
| CH Industri Belling Aps | 5250 Odence Sv | 2009 |
| CH Installasjon AS | Klavestadhaugen | 2025 |
| CH Prosjekt AS | Oslo | 1998 |
| CH Rørleggervakten Trondheim AS | Trondheim | 2026 |
| Chainco Base AS | Svelgen | 1997 |
| Cham Holding AS | Porsgrunn | 2022 |
| Chargenode Europe Nuf | Se-438 91 Landvetter | 2021 |
| Charisma Nuf | Skjoldastraumen | 2023 |
| Charlton Technical Support AS | Sande I Vestfold | 2020 |
| Charmilla Invest AS | Stavanger | 2005 |
| Chcton Holding AS | Stathelle | 2025 |
| Chelitel AS | Slattum | 2016 |
| Chemar Power and Industrial Services Limited Liability Company | Pl-25-647 Kielce | 2008 |
| Chenoa Holding AS | Oslo | 2020 |
| Chenoa Utvikling AS | Oslo | 2017 |
| Chili AS | Lillestrøm | 2023 |
| Chiller Norge AS | Moss | 2010 |
| Chilli Bad AS | Oslo | 2015 |
| Chilloutcamp AS | Åros | 2024 |
| China Communications Construction Company Norway Nuf | Oslo | 2018 |
| Chircu Trygg Bygg AS | Trondheim | 2026 |
| Chirinos Maler AS | Oslo | 2022 |
| Chirita Betongrehabilitering AS | Narvik | 2008 |
| CHJ AS | Bønes | 2018 |
| Chmielinski Maciej Firma Budowlano Remontowa Building | 14-100 Ostroda | 2016 |
| Cho AS | Fredrikstad | 2019 |
| CHR M Vestrheim AS | Kokstad | 1915 |
| CHR Strand Invest AS | Birkeland | 2021 |
| Chrabkowski Ryszard Jaroslaw | 80 299 Gdansk | 2010 |
| Chrag AS | Askim | 2021 |
| Chriar Invest AS | Oslo | 2011 |
| Chricon AS | Kristiansand S | 1998 |
| Chrikema Invest AS | Oslo | 2005 |
| Chrima Invest AS | Kolbeinsvik | 2018 |
| Chris Construct AS | Spikkestad | 2022 |
| Chris Evert Byggtjenester AS | Stathelle | 2025 |
| Christensen & Langeland Da | Krokstadelva | 2009 |
| Christensen & Mathisen AS | Nøtterøy | 1991 |