| Korsgata 42 AS | Real estate | 2023 |
| Kort & Godt AS | Other services | 2000 |
| Kos Holding AS | Financial services | 2009 |
| Koshary AS | Hospitality | 2026 |
| Kostr AS | Construction | 2012 |
| Kostr Powered by Deas AS | Construction | 2025 |
| KR Isolering AS | Construction | 2017 |
| Kraftex AS | Manufacturing | 1974 |
| Kragh Impuls AS | Professional & scientific | 2005 |
| Kransen Tannlegesenter AS | Health & social care | 2012 |
| Krapfoss Industrier AS | Health & social care | 1975 |
| Kreatif AS | Information & communication | 2012 |
| Kreias AS | | 2021 |
| Kresca AS | | 2024 |
| Krescado AS | Information & communication | 2024 |
| Kriba Holding AS | Wholesale & retail | 2005 |
| Kristian a Larsen AS | Professional & scientific | 2021 |
| Kristian Solvang Holding AS | | 2024 |
| Kristiansen Holding AS | Real estate | 1975 |
| Kristiansen Kran & Transport AS | Transport & logistics | 2017 |
| Kristiansen Kran & Transport Holding AS | Transport & logistics | 2017 |
| Kristo Bil AS | Wholesale & retail | 2021 |
| Kristo Rep AS | Manufacturing | 2013 |
| Krogh Revisjon AS | Professional & scientific | 2015 |
| Krossern Holding AS | Professional & scientific | 2022 |
| Krso Eiendom AS | Real estate | 2013 |
| Kråka Fus Kulturbarnehage AS | Education | 2019 |
| Kråkeveien Moss AS | Real estate | 2025 |
| Ktø Invest AS | Real estate | 2023 |
| Kulturhoder AS | Professional & scientific | 2024 |
| Kumla Mek & Hydraulik AB | | 1995 |
| Kure Gård AS | Real estate | 2013 |
| Kureåsen Vann- Og Avløpslag SA | Water & waste | 2024 |
| Kuskjærbukta Bryggelag SA | Real estate | 1961 |
| Kuskjærbukta Brønnlag SA | Water & waste | 1968 |
| Kvalitet AI AS | Information & communication | 2022 |
| Kvalitet Og Pris AS | Wholesale & retail | 2020 |
| Kvalitetshus Hermansen Og Petersen AS | Construction | 2020 |
| Kvalitetsprodukter AS | Wholesale & retail | 2005 |
| Kvernhuset AS | Real estate | 1995 |
| Kvile AS | | 2005 |
| Ky Holding AS | | 2023 |
| Kymar Group AS | Manufacturing | 2011 |
| Kymar Motion AS | Manufacturing | 2010 |
| Kyvco AS | Wholesale & retail | 2012 |
| Kyvco Transport AS | Transport & logistics | 2012 |
| Kåbetekk AS | Financial services | 1953 |
| Kåre Nilsen Holding AS | Real estate | 2007 |
| Körber Supply Chain DK Nuf | Manufacturing | 1999 |
| L Bergstrøm AS | Manufacturing | 2013 |
| L.T. Holding AS | | 2021 |
| La Casa Nostra AS | Other services | 2012 |
| Laar Invest AS | Professional & scientific | 2024 |
| Labelcraft AS | Information & communication | 1998 |
| Labolo AS | Wholesale & retail | 2009 |
| Laboremus Eiendom AS | Real estate | 1995 |
| Labpro Konsult AS | Professional & scientific | 2025 |
| Lagi Bar AS | Hospitality | 2023 |
| Lagstyrke AS | Education | 2005 |
| Laien AS | Professional & scientific | 2016 |
| Lakaz AS | Real estate | 2025 |
| Langbråten Entreprenør AS | Construction | 2013 |
| Langenbergs El & Industriservice AB | Construction | 2007 |
| Language Consultant AS | Education | 2017 |
| Lark Invest AS | Professional & scientific | 1985 |
| Lars Forfang AS | Financial services | 2005 |
| Lasse Kavli Holding AS | | 2020 |
| Lasse Pettersen AS | Manufacturing | 1992 |
| Last Data AS | Information & communication | 2026 |
| Lauritzen Vault AS | Real estate | 2011 |
| Lavida Consulting AS | Information & communication | 2000 |
| Lawa Holding AS | Health & social care | 2020 |
| Laxbar AS | Professional & scientific | 2012 |
| LB Bygg AS | Construction | 2019 |
| LB Bygg AS | Construction | 2023 |
| LB Bygg Holding AS | | 2023 |
| Leadership Power Da | Professional & scientific | 2007 |
| Leadjabber AS | Information & communication | 2012 |
| Leanspire AS | Professional & scientific | 2026 |
| Legekontoret I Moss Da | Health & social care | 2012 |
| Leif Thorvaldsen AS | Construction | 2016 |
| Lem AS | Financial services | 2014 |
| Len Invest AS | Wholesale & retail | 2010 |
| Lenes Fotterapi AS | Health & social care | 2020 |
| Lerke Bod AS | Real estate | 2012 |
| Lexow Låsservice AS | Wholesale & retail | 2004 |
| Lexum AS | Administrative & support | 2017 |
| Lfgt Invest AS | | 2025 |
| LGV Holding AS | Real estate | 2016 |
| LHB Holding AS | Administrative & support | 1999 |
| Lians Renhold AS | Administrative & support | 2021 |
| Liberta AS | Real estate | 2026 |
| Libra Consult AS | | 2018 |
| Lift N Run Kambo AS | Arts & recreation | 2025 |
| Liga AS | Administrative & support | 2001 |
| Lille Interiør AS | Wholesale & retail | 2010 |
| Lilleberg Development AS | Information & communication | 2020 |
| Lilleeng Legesenter AS | Health & social care | 2015 |
| Lillestrøm Taxi AS | Transport & logistics | 2024 |
| Lilly Capital AS | | 2025 |