| Troya Montering Ans | Sandnes | 2009 |
| TRP - Bygg AS | Tromsø | 2023 |
| TRS Bygg AS | Steinberg | 2019 |
| Trss Group AS | Oslo | 2021 |
| Trudvang Eiendom AS | Norheimsund | 2005 |
| Trudvang Og Brandsborg AS | Haslum | 2008 |
| True Colors Maling AS | Son | 2022 |
| Truls & Petter Rørleggerservice AS | Paradis | 2003 |
| Truls Holm AS Maskinentreprenør | Eidsvoll | 1988 |
| Truls Tørrisplass AS | Nesbyen | 2006 |
| Truls Vold Bygg- Og Graveservice AS | Sande I Vestfold | 2020 |
| Trulssen Maskin AS | Moen | 2011 |
| Trulssen VVS AS | Stabbestad | 2011 |
| Trust Technologies AS | Reistad | 2019 |
| Trust Vaktmester Og Byggetjeneste AS | Fjerdingby | 2014 |
| TRW Bygg AS | Larvik | 2025 |
| Try Rør AS | Søgne | 2000 |
| Trybi AS | Bekkestua | 2005 |
| Tryblikk AS | Trysil | 1987 |
| Trydal Holding AS | Sandefjord | 2022 |
| Trydal Invest AS | Søgne | 2007 |
| Trydal Maskin AS | Gjerstad | 2003 |
| Trydal Service AS | Søgne | 2021 |
| Trygg Bygg&Rør AS | Oslo | 2022 |
| Trygg Byggpartner AS | Oslo | 2016 |
| Trygg Elektriske AS | Greåker | 2016 |
| Trygg Elektro AS | Oslo | 2019 |
| Trygg Entreprenør AS | Østerås | 2020 |
| Trygg Håndverk AS | Oslo | 2020 |
| Trygg Lek Da | Sylling | 1994 |
| Trygg Malerservice AS | Drammen | 2022 |
| Trygg På Bygg AS | Nodeland | 2025 |
| Trygg Rør Og Totalbad AS | Kongsberg | 2022 |
| Trygg Tak AS | Heimdal | 2025 |
| Trygg Takservice AS | Søfteland | 2025 |
| Trygg VVS AS | Oslo | 2012 |
| Trygg-Bygg AS | Oslo | 2013 |
| Tryggbygg 24 AS | Moss | 2024 |
| Tryggbygg AS | Reinsvoll | 2025 |
| Trygger AS | Vestby | 2024 |
| Tryggmur AS | Oslo | 2025 |
| Tryggvason Bygg Og Montasje AS | Trondheim | 2017 |
| Trygt Hus AS | Hemnes | 2013 |
| Trygt Innemiljø AS | Moss | 2019 |
| Trygve Aanensen AS | Kristiansand S | 1994 |
| Trygve Espeland Murarforretning AS | Kaupanger | 1993 |
| Trygve Investment AS | Melandsjø | 2016 |
| Trygve J. Sjøen Investering AS | Åkrehamn | 2012 |
| Trygve Martinsen & Sønn AS | Bøstad | 1992 |
| Trygve Rye-Johnson AS | Andebu | 2014 |
| Trygve Ullaland AS | Florø | 1998 |
| Trym Company AS | Brumunddal | 2003 |
| Tryma AS | Oslo | 2002 |
| Trysil 860 AS | Trysil | 2013 |
| Trysil Elektro AS | Trysil | 1999 |
| Trysil Entreprenør AS | Trysil | 2018 |
| Trysil Flis & Malersenter AS | Trysil | 1997 |
| Trysil Kjøle & Varmeteknikk AS | Ljørdalen | 2026 |
| Trysil Linjebygg AS | Nybergsund | 1973 |
| Trysil Maskinutleie AS | Trysil | 2017 |
| Trysil Massivtre AS | Slettås | 2020 |
| Trysil Mesterbygg AS | Jordet | 2022 |
| Trysil Mur Og Puss AS | Trysil | 2000 |
| Trysil Prosjektutvikling AS | Trysil | 2019 |
| Trysil Rør Holding AS | Trysil | 2023 |
| Trysil Rørleggerbedrift AS | Trysil | 2023 |
| Trysil Varmepumpe AS | Trysil | 2020 |
| Trysilanlegg AS | Tynset | 2019 |
| Trysilbygg AS | Drammen | 1990 |
| Trysilfjell Hytter AS | Trysil | 2013 |
| Trysilhus Boligservice AS | Drammen | 2015 |
| Trysilsetra Service AS | Sandvika | 2013 |
| Trädgårdsanläggning I Sjuhärad AB Nuf | Se-506 30 Borås | 2026 |
| Trå Byggservice AS | Vigra | 2022 |
| Trå Snekkerservice AS | Lindås | 2020 |
| Tråkk Stiutvikling AS | Sauda | 2024 |
| Trædal Invest AS | Kristiansand S | 2021 |
| Træna Snekkerservice AS | Træna | 2016 |
| Trøan VVS AS | Heimdal | 2025 |
| Trøen Maskin AS | Rendalen | 2022 |
| Trøiterud Bygg AB | Se-780 67 Sælen | 2011 |
| Trømborg Ventilasjonspartnere AS | Askim | 2006 |
| Trøndelag Betong AS | Levanger | 2016 |
| Trøndelag Betongsprøyting AS | Verdal | 1987 |
| Trøndelag Blåseisolering AS | Sparbu | 2019 |
| Trøndelag Brønnboring AS | Trondheim | 2007 |
| Trøndelag Bygg Og Våtrom AS | Saksvik | 2025 |
| Trøndelag Byggtjenester AS | Levanger | 2017 |
| Trøndelag Elektro AS | Stjørdal | 1997 |
| Trøndelag Entreprenør AS | Vuku | 2011 |
| Trøndelag Fasadevask AS | Verdal | 2022 |
| Trøndelag Fjell & Anlegg AS | Soknedal | 2022 |
| Trøndelag Fjellboring AS | Spongdal | 2012 |
| Trøndelag Forskaling AS | Verdal | 1994 |
| Trøndelag Freseservice AS | Trondheim | 2022 |
| Trøndelag Klima Service AS | Oslo | 2023 |
| Trøndelag Klima Service Utleie AS | Levanger | 2026 |
| Trøndelag Kuldeteknikk AS | Verdal | 2016 |
| Trøndelag Malerservice AS | Stjørdal | 2024 |
| Trøndelag Montasje AS | Ler | 2023 |