| Kanalen Pizza Og Nattcafe Ans | Hospitality | 1991 |
| Kanat Da | Wholesale & retail | 2004 |
| Kaptein Rødskjegg Ans | Arts & recreation | 2004 |
| Kara Partners Da | Professional & scientific | 2017 |
| Karat Bistand AS | Professional & scientific | 1991 |
| Karat Regnskap AS | Professional & scientific | 2013 |
| Karender Og Fornes Da | Construction | 2002 |
| Karl Vegard Antonsen AS | | 2019 |
| Karlann AS | Construction | 2025 |
| Karosserimakeren AS | Real estate | 2005 |
| Kartoffelkompaniet AS | Financial services | 2016 |
| Karusell Second Hand AS | Real estate | 2020 |
| Kase Holding AS | Health & social care | 2005 |
| Kase-Berg AS | Health & social care | 2006 |
| Kasima Invest AS | | 2023 |
| Kastana AS | | 2024 |
| Kastplast AS | Information & communication | 2019 |
| Katsol Snekker AS | Construction | 2026 |
| Katuranus AS | Arts & recreation | 2012 |
| Kavi Industri AS | Professional & scientific | 2011 |
| KB Gulv Ans | Manufacturing | 1988 |
| KB18 Norge | Professional & scientific | 2020 |
| KC Holding AS | Professional & scientific | 2017 |
| Ke Wi Invest AS | | 2021 |
| Kebab Huset AS | Hospitality | 2019 |
| Kebab Kompaniet AS | Hospitality | 2017 |
| Kefill Holding AS | | 2024 |
| Kenneh Consulting AS | Information & communication | 2022 |
| Kevin Kliland Holding AS | Information & communication | 2005 |
| Keys AS | Wholesale & retail | 2016 |
| KG Invest AS | Real estate | 2007 |
| KG Utvikling 2 AS | Real estate | 2007 |
| Khawaja Invest AS | Real estate | 2019 |
| Kias Reklame AS | Professional & scientific | 2017 |
| Kilen Vannverk SA | Water & waste | 1982 |
| Kilikrumins AS | Arts & recreation | 2012 |
| Killeman AS | Real estate | 2025 |
| Kim Erik Vinje Invest AS | | 2020 |
| Kimpo Holding AS | Construction | 2022 |
| Kimpo Norge AS | Construction | 2001 |
| Kinitro AS | | 2019 |
| Kinitro Omsorg AS | Professional & scientific | 2026 |
| Kioskdrift Solveig Lund AS | Wholesale & retail | 2025 |
| Kirkeby Solutions AS | Professional & scientific | 2022 |
| Kiropraktisk Klinikk Da | Health & social care | 1999 |
| Kiropraktisk Klinikk Da | Health & social care | 2004 |
| Kiserud Holding AS | | 2023 |
| Kjetil Skovdahl Invest AS | | 2005 |
| KJH Eiendom AS | Real estate | 1987 |
| KJK Maskinservice Moss AS | Wholesale & retail | 2001 |
| Kjusa Deg AS | | 2023 |
| Kjøkken Studio Moss AS | Wholesale & retail | 2022 |
| Kjøkkendrift No 1 Rygge AS | Wholesale & retail | 2017 |
| Kjøkkensenteret Østfold Nord AS | Wholesale & retail | 2021 |
| KKL Invest AS | Financial services | 2024 |
| Kla-Tjenester AS | Professional & scientific | 2011 |
| Klara AS | Real estate | 2013 |
| Klima Og Ventilasjon AS | Construction | 2022 |
| Klinikk for Tinnitus Og Hyperakusis AS | Health & social care | 2025 |
| Klinikken for Han & Henne Medispa AS | Other services | 2012 |
| Klinikken Til Wenche AS | Health & social care | 2021 |
| Klistra Norway AS | Wholesale & retail | 2021 |
| Klock Bistand AS | Professional & scientific | 2025 |
| Klock Holding AS | | 2023 |
| Klostergata 7A AS | Real estate | 2025 |
| Klostergata Eiendomsutvikling AS | Real estate | 1991 |
| Klovn Invest AS | Real estate | 2012 |
| Klovnefabrikken AS | Arts & recreation | 2025 |
| Knapp AS | Wholesale & retail | 2006 |
| Knausen Holding AS | Wholesale & retail | 2014 |
| Knips AS | Information & communication | 2021 |
| Knowledgetrack AS | Education | 2003 |
| Knudsen Drift Og Eiendom AS | Construction | 2014 |
| Knut Einar Veum AS | Real estate | 1933 |
| Knut Helgesen & Sønner AS | Construction | 2007 |
| Knut-Herman Andreassen AS | Wholesale & retail | 2018 |
| Kobberbjørn AS | Wholesale & retail | 2023 |
| Kobbervikdalen Næringseiendom AS | Real estate | 2017 |
| Kobär AS | Administrative & support | 2021 |
| Kodetank AS | Information & communication | 2019 |
| Kojak Holding AS | Real estate | 2019 |
| Kolo AS | Construction | 2017 |
| Kolsrød AS | Construction | 2012 |
| Kompass Mat AS | Hospitality | 2012 |
| Kompetanseutleie AS | Information & communication | 2020 |
| Komplettøkonomi AS | | 2025 |
| Komtek AS | Professional & scientific | 1995 |
| Kong Krete AS | Construction | 2019 |
| Kongens Gate 26 AS | Real estate | 2014 |
| Kongensgate 20C Skien AS | Real estate | 2023 |
| Kongensgate 32 AS | Real estate | 1922 |
| Kongensgate 36 AS | Real estate | 2011 |
| Kongensgate 5 Moss AS | Real estate | 2014 |
| Konsert Teknikk AS | Arts & recreation | 2014 |
| Konsulentbyrået 7K AS | Education | 1997 |
| Konturklinikken AS | Other services | 2012 |
| Koriander AS | Real estate | 2025 |
| Koriander Moss AS | Hospitality | 2020 |
| Koriander Værstetorvet AS | Hospitality | 2025 |
| Korni Holding AS | Real estate | 2025 |