| J.A. Maskin AS | Sandefjord | 2009 |
| J.A.Rørservice AS | Kråkstad | 2013 |
| J.B. Ugland Entreprenør AS | Grimstad | 2011 |
| J.Barnsley Cranes Ltd Nuf | Dy5 1Tj-Brierley Hill, West Midland | 2018 |
| J.Enevoldsen Holding AS | Narvik | 2021 |
| J.Ersvik Graving Og Transport AS | Tverlandet | 1997 |
| J.Frydenlund Holding AS | Furnes | 2023 |
| J.H Rørleggerservice AS | Greåker | 2023 |
| J.H.K. Holding AS | Leknes | 2005 |
| J.Hyttebakk AS | Rennebu | 2024 |
| J.I Håndverk Service AS | Halden | 2025 |
| J.I.Bakken Graveservice AS | Vestmarka | 2023 |
| J.J.A. Holding AS | Oslo | 2023 |
| J.K Bygg AS | Narvik | 2023 |
| J.K Holding AS | Ridabu | 2016 |
| J.K. Fosse Bygg AS | Husøysund | 2013 |
| J.K. Invest AS | Røyse | 2008 |
| J.L. Byggtjenester AS | Fosslandsosen | 2023 |
| J.M Bygg AS | Alta | 2012 |
| J.M Bygg Montasje AS | Langangen | 2020 |
| J.M Holding AS | Alta | 2017 |
| J.M.Bygg AS | Gibostad | 2010 |
| J.O Flemsæter AS | Angvik | 2015 |
| J.O Rør AS | Alta | 2025 |
| J.O.G. Holding AS | Melhus | 2006 |
| J.O.T. Bredesen Invest AS | Grøa | 2005 |
| J.R. Nordkvelde AS | Kvelde | 2012 |
| J.S Entreprenør AS | Hagan | 2022 |
| J.Thormodsen Invest AS | Erdal | 2019 |
| J.V Tømrer Og Snekkerservice Da | Sandefjord | 2007 |
| J.W Renovering & Bygg Jerry Wallerstedt | 585 91 Lindköping | 2010 |
| J3M Norge AS | Oslo | 2025 |
| J3M Structure AB Nuf | Se-333 31 Smålandsstenar | 2026 |
| Ja Anleggsdrift AS | Øyer | 2014 |
| Ja Bygg Og Betong AS | Talvik | 2017 |
| Ja Byggpro AS | Asker | 2023 |
| Ja Entreprenør AS | Øyer | 2014 |
| Ja Fuglesteg AS | Skjolden | 2024 |
| Ja Gulvsystemer AS | Frosta | 2019 |
| Ja Montasje AS | Iveland | 2023 |
| Ja Re Eiendom AS | Fitjar | 1992 |
| Ja Tanksystemer AS | Frosta | 2026 |
| Ja VVS AS | Frogner | 2021 |
| Ja&Ra AS | Hommersåk | 2012 |
| Ja-To Elektro AS | Geithus | 1996 |
| Jaa Byggservice AS | Landåsbygda | 2026 |
| Jaas Industriservice AS | Surnadal | 2019 |
| Jab Anleggservice AS | Vigra | 2019 |
| Jabar AS | Ulefoss | 2015 |
| Jabra Maskin AS | Bagn | 2015 |
| Jac Holding AS | Moss | 2017 |
| Jacek Gorski - Remontowo -Budowlana | 84-200 Wejherowo | 2006 |
| Jacek Gubala | Oslo | 2008 |
| Jacek Snekker Og Flis AS | Sørkjosen | 2015 |
| Jacek Szarycki - Usl Budowlane | Sarpsborg | 2006 |
| Jack AS | Oslo | 2022 |
| Jackpol Jacek Zgutka Uslugi Remontowobudowlane Nuf | 26-600 Radom | 2014 |
| Jacks Rehab Og Montasje AS | Kolbu | 2020 |
| Jackson Constructions AS | Skollenborg | 2021 |
| Jackvi AS | Arendal | 2021 |
| Jaco Elektro AS | Alta | 2000 |
| Jaco Service AS | Fjellhamar | 2012 |
| Jacobs Tonset Holding AS | Kråkerøy | 2023 |
| Jacobsen & Co AS | Moltustranda | 1924 |
| Jacobsen Bygg Og Maskin AS | Hof | 2024 |
| Jacobsen Elektro Holding AS | Lierstranda | 1983 |
| Jacobsen Rør AS | Stavanger | 2012 |
| Jacobsen Snekkerservice AS | Bosberg | 1995 |
| Jacobsen Utleie Og Tjenester AS | Gol | 2025 |
| Jacobsen VVS AS | Bjorbekk | 2005 |
| Jada Styling AS | Undrumsdal | 2019 |
| Jadarhus AS | Stavanger | 1994 |
| Jadarhus Bygg AS | Stavanger | 2007 |
| Jadarhus Gruppen AS | Stavanger | 2008 |
| Jadefo Holding AS | Mjøndalen | 2010 |
| Jaeggi Hybridtechnologie AG Nuf | Ch-4051 Basel | 2026 |
| Jag Betong AS | Lillesand | 2023 |
| Jag Bygg AS | Kvinesdal | 2012 |
| Jaggu AS | Steinkjer | 2024 |
| Jagi Bygg AS | Giske | 2026 |
| Jagiello Husrenovering AS | Vinstra | 2024 |
| Jagima Drift AS | Grimstad | 2012 |
| Jaglass AS | Gressvik | 2017 |
| Jah Bygg AS | Nannestad | 2021 |
| Jah Elektro AS | Holmestrand | 2008 |
| Jahbygg Norge AS | Mosjøen | 2026 |
| Jahbygg Oü Nuf | Mosjøen | 2012 |
| Jahic Invest AS | Drammen | 2012 |
| Jaho Mur Holding AS | Søgne | 2021 |
| Jaho Mur Og Fasade AS | Søgne | 2020 |
| Jahr Maskin AS | Åmot | 2018 |
| Jahr Transport AS | Holter | 1996 |
| Jahre & Jahre Holding AS | Auli | 2012 |
| Jahren Overflate AS | Bergen | 2022 |
| Jahren Rør AS | Sandefjord | 2026 |
| Jakhelln AS | Lillestrøm | 1969 |
| Jakhelln Entreprenør AS | Lillestrøm | 1996 |
| Jakob Blikra Maskinstasjon AS | Vikedal | 2008 |
| Jakob Og Norman Moldestad Ans | Kopervik | 1996 |
| Jakob Opdal AS | Trondheim | 1999 |