| Aakre Anlegg AS | Haramsøy | 2012 |
| Aakvik Bygg Og Eiendom AS | Bø I Telemark | 2012 |
| Aaland AS | Åmli | 2005 |
| Aaland Elektroservice AS | Flisa | 2021 |
| Aalberg & Kattem Ans | Trondheim | 1995 |
| Aalborg El-Teknikk Aps Nuf | Dk-9210 Aalborg Sø | 2025 |
| Aalerudmyra AS | Oslo | 2012 |
| Aaleskjær Elektro AS | Vesterøy | 2022 |
| Aalgaard Bygg AS | Sandnes | 2011 |
| Aalmo AS Autorisert Elektroentreprenør | Trondheim | 1991 |
| Aalmo El & Sceneteknikk AS | Trondheim | 2020 |
| Aaltvedt Snekkerservice AS | Porsgrunn | 2024 |
| Aamlid & Co AS | Sola | 2025 |
| Aamlid Invest AS | Birkeland | 2005 |
| Aamlid Invest Bygg AS | Birkeland | 2013 |
| Aamodt AS | Kristiansand S | 2015 |
| Aamodt Bygg AS | Kristiansand S | 2015 |
| Aamodt Bygg Og Hage AS | Stavanger | 2021 |
| Aamodt Entreprenør AS | Sykkylven | 2022 |
| Aamodt Rør I Sør AS | Søgne | 1999 |
| Aamodt Støpeservice AS | Askim | 2025 |
| Aamodts Blikk Og Ventilasjon AS | Kristiansand S | 2007 |
| Aamot AS | Nordberg | 2020 |
| Aandal & Haugland Bygg AS | Rygge | 2015 |
| Aanensen Bygg AS | Søndeled | 2021 |
| Aanerud Entreprenør AS | Oslo | 1992 |
| Aanestad AS | Son | 2018 |
| Aanestad Elektro AS | Nærbø | 1980 |
| Aanonsen Maritime Bygg AS | Færvik | 2024 |
| Aanonsen VVS AS | Arendal | 2013 |
| Aarbakk Maskin AS | Notodden | 2008 |
| Aardal Bygg AS | Levanger | 2010 |
| Aarhaugen AS | Ler | 2025 |
| Aarhus Anlegg AS | Frekhaug | 2020 |
| Aarland Bygg & Eiendomsutvikling AS | Stolmen | 2004 |
| Aarli AS | Froland | 2018 |
| Aarmo's Pre Bygg AS | Skage I Namdalen | 2005 |
| Aarredahl Consulting AS | His | 2005 |
| Aars Invest AS | Oslo | 1995 |
| Aarsand Holding AS | Hommersåk | 2022 |
| Aarset Bygg Og Installasjon AS | Olsvik | 2001 |
| Aarseth Boligventilasjon AS | Frogner | 2006 |
| Aarskog & Helland Bygg AS | Fitjar | 2021 |
| Aarskog Elektro AS | Fitjar | 2016 |
| Aarsland Maskin Da | Kvernaland | 2026 |
| Aarsleff Fundamentering & Boring AS | Ulefoss | 2006 |
| Aarsleff Ground Engineering AB Nuf | 424 57 Gunnilse | 2019 |
| Aarsleff Rail AS | Trondheim | 2020 |
| Aarsleff Rail Nuf | Trondheim | 2017 |
| Aarsleff Rail Sweden Nuf | Se-216 26 Malmö | 2014 |
| Aarsleff Rohrsanierung GmbH | De-90552 Röthenbach/Pegnitz | 2026 |
| Aarsrud Bygg AS | Oslo | 2023 |
| Aarstad Anlegg AS | Inderøy | 2022 |
| Aarstad Gruppen AS | Inderøy | 2022 |
| Aarstad Maskin AS | Inderøy | 2026 |
| Aarstad Rør & Grøfteservice AS | Egersund | 2022 |
| Aarstad Rør & Mekaniske AS | Egersund | 2024 |
| Aarvik Byggmester AS | Os | 1987 |
| Aarvik Drift AS | Os | 2019 |
| Aarvik Utvikling AS | Os | 2020 |
| Aarvikgruppen AS | Os | 2019 |
| Aarvold Holding AS | Raufoss | 2016 |
| Aas & Nordal AS | Nannestad | 1998 |
| Aas & Vidringstad Bygg AS | Vanse | 2021 |
| Aas Driftslag Da | Engesland | 2002 |
| Aas Maskin AS | Notodden | 2015 |
| Aas Maskinentreprenør AS | Sørarnøy | 2020 |
| Aas Og Høiland AS | Lyngdal | 1986 |
| Aas Olsen Maskin AS | Tydal | 2018 |
| Aas Rørleggerservice AS | Sistranda | 1993 |
| Aas Stillasservice AS | Hamar | 2003 |
| Aasand Byggservice AS | Eggedal | 2017 |
| Aasbekken AS | Hov | 2025 |
| Aasbygg AS | Åsen | 2026 |
| Aase & Svendsen AS | Sævelandsvik | 2020 |
| Aase & Svendsen Holding AS | Sævelandsvik | 2017 |
| Aase Bygg & Betong AS | Førde | 2023 |
| Aase Rør AS | Sandnes | 2013 |
| Aase Trearbeid AS | Seljord | 2022 |
| Aasebø & Ulvestad Installasjon AS | Volda | 1997 |
| Aasebø Betongentreprenør AS | Kleppestø | 2021 |
| Aasebø Fasade AS | Kleppestø | 2022 |
| Aasebø Holding AS | Hauglandshella | 2015 |
| Aasebø Murservice AS | Kleppestø | 2013 |
| Aasemyr Anleggsservice AS | Volda | 2023 |
| Aasen & Ingolfsrud Da | Notodden | 2001 |
| Aasen Alarm AS | Namsos | 2014 |
| Aasen Bygg AS | Tolga | 2016 |
| Aasen Elektro AS | Horten | 2024 |
| Aasen Maskin AS | Kvisvik | 1989 |
| Aasen Maskin AS | Isdalstø | 1998 |
| Aasen Maskin Og Transport AS | Tustna | 2005 |
| Aasen Uteservice AS | Førde | 2026 |
| Aasetera Hytteservice Da | Nord-Torpa | 2006 |
| Aasgaardstrand Bygg AS | Åsgårdstrand | 2015 |
| Aasgard Bygg AS | Børsa | 2018 |
| Aasheim Bygg AS | Tessanden | 2017 |
| Aasheim Elektro AS | Maura | 2020 |
| Aasheim Elektro AS | Maura | 2026 |
| Aasheim Entreprenør AS | Tomter | 2023 |