| Siviling Anders Balstad AS | Sandvika | 2015 |
| Siviling. E. Hagen AS | Sandnes | 2021 |
| Siviling. J.B. Andersen AS | Kristiansand S | 2013 |
| Sivilingeniør a Helsem AS | Tiller | 1986 |
| Sivilingeniør Albert Ølnes AS | Fagerstrand | 2005 |
| Sivilingeniør Anders Haugen AS | Nittedal | 2012 |
| Sivilingeniør Asbjørn Andersen Byggrådgivning AS | Hamar | 2017 |
| Sivilingeniør Audun Fossum AS | Oslo | 2024 |
| Sivilingeniør Bjarte Fyllingen AS | Fyllingsdalen | 1984 |
| Sivilingeniør Bård Sørensen AS | Stokmarknes | 2003 |
| Sivilingeniør Dag R. Stensaas AS | Børsa | 2019 |
| Sivilingeniør Daniel Nesset AS | Finstadjordet | 2019 |
| Sivilingeniør Eiliv Skomedal AS | Sandnes | 2016 |
| Sivilingeniør Eirik Botnmark AS | Årnes | 2014 |
| Sivilingeniør Espen Thøgersen AS | Torp | 2024 |
| Sivilingeniør Forsberg AS | Verdal | 2019 |
| Sivilingeniør Geir a Hilde AS | Asker | 1995 |
| Sivilingeniør Geir Moe AS | Porsgrunn | 2020 |
| Sivilingeniør Giert Aasheim AS | Bekkestua | 1970 |
| Sivilingeniør Gjestad AS | Skåla | 2006 |
| Sivilingeniør Godhavn AS | Trondheim | 1986 |
| Sivilingeniør Gøran Skogvoll AS | Sortland | 2025 |
| Sivilingeniør Haakon Aasbø AS | Kristiansand S | 2011 |
| Sivilingeniør Hans Petter Jensen AS | Oslo | 2005 |
| Sivilingeniør Helge Hopen AS | Bergen | 2005 |
| Sivilingeniør Holmefjord AS | Førde | 1998 |
| Sivilingeniør Håkon Hjartnes AS | Norheimsund | 2020 |
| Sivilingeniør Håkon Langseth AS | Mo I Rana | 1998 |
| Sivilingeniør Håkon Seljåsen AS | Arendal | 2017 |
| Sivilingeniør Isebakke AS | Skjeberg | 2026 |
| Sivilingeniør Ivar Bjarte Nord AS | Nordfjordeid | 2012 |
| Sivilingeniør Ivar Strand AS | Snertingdal | 1992 |
| Sivilingeniør Jan Roness AS | Mandal | 1990 |
| Sivilingeniør Johan Tjåland AS | Brusand | 2023 |
| Sivilingeniør Jon-Arild Andreassen AS | Horten | 2014 |
| Sivilingeniør K. Ekornrud AS | Etne | 2005 |
| Sivilingeniør Knut Mørkeseth AS | Tranby | 1998 |
| Sivilingeniør Knutson AS | Narvik | 2018 |
| Sivilingeniør Kolloen AS | Drammen | 2024 |
| Sivilingeniør Lars Tangerås AS | Skien | 2025 |
| Sivilingeniør Larsen AS | Vikebygd | 2022 |
| Sivilingeniør Leif Johan Røthe AS | Torvastad | 2012 |
| Sivilingeniør Leif K Lunke AS | Haslum | 1993 |
| Sivilingeniør Magnus Krogh Strøm AS | Oslo | 2020 |
| Sivilingeniør Mørkrid AS | Oppegård | 1990 |
| Sivilingeniør Nils Rømoen AS | Lillehammer | 2007 |
| Sivilingeniør O D Lundekvam AS | Ulset | 2014 |
| Sivilingeniør Oddvar Birkeland AS | Konsmo | 2008 |
| Sivilingeniør Oddvar Reiakvam AS | Naustdal | 2015 |
| Sivilingeniør Olaf Rømcke AS | Drammen | 2022 |
| Sivilingeniør Ole a. Westberg AS | Lysaker | 2007 |
| Sivilingeniør Ole Hammari AS | Alta | 2013 |
| Sivilingeniør Ottar Skjerve AS | Kolsås | 2018 |
| Sivilingeniør Ottar Skjervheim AS | Voss | 2010 |
| Sivilingeniør Owrenn AS | Elverum | 1975 |
| Sivilingeniør Per Bjerke AS | Gressvik | 2025 |
| Sivilingeniør Petter Kloster AS | Bergen | 2004 |
| Sivilingeniør Robert Williamsen AS | Namsos | 2000 |
| Sivilingeniør Rodvelt AS | Sandnes | 1988 |
| Sivilingeniør Roger Daniloff AS | Tananger | 2019 |
| Sivilingeniør Ræder AS | Tromsø | 2021 |
| Sivilingeniør Sam Lorgen AS | Ålesund | 1975 |
| Sivilingeniør Stein Kjæve AS | Larkollen | 2006 |
| Sivilingeniør Steinar Aamo AS | Saupstad | 2015 |
| Sivilingeniør Stig Hole AS | Paradis | 2005 |
| Sivilingeniør SV Bolkesjø Ans | Oslo | 1987 |
| Sivilingeniør Svein Andersen AS | Nannestad | 2015 |
| Sivilingeniør Sverre Christensen AS | Drøbak | 1997 |
| Sivilingeniør Sverre Steen AS | Fredrikstad | 1994 |
| Sivilingeniør Taras Trofymchuk AS | Froland | 2021 |
| Sivilingeniør Terje Økland AS | Hokksund | 2021 |
| Sivilingeniør Tore Johan Smidt AS | Nesttun | 2022 |
| Sivilingeniør Torstein Lajord AS | Rykkinn | 1998 |
| Sivilingeniør Trond Mellerud AS | Bodø | 2013 |
| Sivilingeniør Vang AS | Harstad | 2012 |
| Sivilingeniør Vegard Bakken AS | Kristiansund N | 2023 |
| Sivilingeniør Will Arentz AS | Drammen | 2002 |
| Sivilingeniør Øyvind N. Nielsen AS | Asker | 1987 |
| Sivilingeniørene Harboe Og Leganger AS | Trondheim | 2009 |
| Sivilingeniørene Haug Og Blom-Bakke AS | Oslo | 1987 |
| Sivilingeniørene Julsen & Poppe AS | Fredrikstad | 2005 |
| Sivilingeniørene Stensaker AS | Billingstad | 2000 |
| Siviløkonom Ola Karlsen AS | Harstad | 1991 |
| Siviløkonom Asgeir Rotevatn AS | Ålesund | 1996 |
| Siviløkonom Bent Bugge AS | Lysaker | 1994 |
| Siviløkonom Knut H Pedersen AS | Porsgrunn | 1987 |
| Siviløkonom Martin Steinar Hagen AS | Sande I Vestfold | 2013 |
| Siviløkonom Nils Sverreson AS | Drammen | 2026 |
| Siviløkonom Ole Kristian Solum AS | Helle | 2005 |
| Siviløkonom Ove Ellingsen AS | Sogndal | 2019 |
| Siviløkonom Per Øyvind Trydal AS | Drammen | 2005 |
| Siviløkonom Rune Øidne Reinertsen AS | Kristiansand S | 2022 |
| Siviløkonom Thormodsæter AS | Åkrehamn | 2005 |
| Siviløkonom Tor Henriksen AS | Svolvær | 2007 |
| Sivm AS | Ellingsøy | 2020 |
| Sivos AS | Sandnes | 2019 |
| Sivra AS | Storslett | 2007 |
| Sivtek AS | Sandnes | 2005 |
| Siw Hege Mortensen AS | Kirkenes | 2016 |
| Siwen Consulting AS | Kongsberg | 2019 |