| Intellikode AS | Information & communication | 2025 |
| Interimspesialisten AS | Professional & scientific | 2026 |
| Interiørkupp AS | Wholesale & retail | 2020 |
| Internasjonale Messetjenester AS | Administrative & support | 2010 |
| Intersport Norge AS | Wholesale & retail | 2020 |
| Invest Helse AS | Health & social care | 2021 |
| Iso-Iwepp Limited Nuf | Professional & scientific | 2015 |
| Isolasjonsfirma H J Lundemo AS | Construction | 1993 |
| Istudio AS | Information & communication | 1996 |
| Isvoria AS | Information & communication | 2023 |
| IT Board AS | Information & communication | 2023 |
| IT Innovasjon AS | Information & communication | 2014 |
| IT Ledelse- Design & Drift AS | Information & communication | 2021 |
| Itpd AS | Professional & scientific | 2026 |
| Ivar Transport AS | Transport & logistics | 2019 |
| Jac AS | Hospitality | 2011 |
| Jacobsgata 2 AS | Real estate | 2001 |
| Jahren Eiendom AS | Real estate | 2010 |
| Jakg Holding AS | Real estate | 2013 |
| Jaktia Jessheim AS | Wholesale & retail | 2019 |
| Jalapemo Holding AS | | 2021 |
| James IV AS | Real estate | 2016 |
| James Strong AS | Real estate | 2015 |
| Jan Østberg Liftservice AS | Wholesale & retail | 1995 |
| Japundzic Invest AS | Construction | 2023 |
| Jar Shipagency Nuf | Transport & logistics | 2010 |
| JB Interiør AS | Construction | 2019 |
| Je Fosshaug Holding AS | Real estate | 2019 |
| Jensens Binge AS | | 2021 |
| Jep Konsult AS | Professional & scientific | 2010 |
| Jernbanegata 20 Eiendom Da | Real estate | 2006 |
| Jerv Invest AS | | 2023 |
| Jes Investments AS | Financial services | 2014 |
| Jess Bazar AS | Wholesale & retail | 2019 |
| Jess Kjøtt AS | Wholesale & retail | 2025 |
| Jessheim Arkitekter AS | Professional & scientific | 2016 |
| Jessheim Asfalt AS | Manufacturing | 2022 |
| Jessheim Auto AS | Wholesale & retail | 2021 |
| Jessheim Auto Senter AS | Wholesale & retail | 2011 |
| Jessheim Bilpartner AS | Wholesale & retail | 2024 |
| Jessheim Bilpleie Senter AS | Other services | 2018 |
| Jessheim Bilskade AS | Other services | 2006 |
| Jessheim Bygg Og Maler AS | Construction | 2025 |
| Jessheim Byutvikling AS | Real estate | 1906 |
| Jessheim C & V Tires Da | Wholesale & retail | 2002 |
| Jessheim Danseskole AS | Education | 2014 |
| Jessheim Dyreklinikk AS | Professional & scientific | 2012 |
| Jessheim Eidsvoll Tannlegevakt AS | Health & social care | 2021 |
| Jessheim Eiendomsforvaltning AS | | 2005 |
| Jessheim Fysikalske AS | Health & social care | 2025 |
| Jessheim Grill Og Curry AS | Hospitality | 2015 |
| Jessheim Gym AS | Arts & recreation | 2014 |
| Jessheim Handel AS | Wholesale & retail | 1992 |
| Jessheim Kiropraktikk Holding AS | | 2026 |
| Jessheim Marked AS | Other services | 2021 |
| Jessheim Medisinske Senter AS | Health & social care | 2023 |
| Jessheim Minilager AS | Real estate | 2023 |
| Jessheim Multimedia AS | Wholesale & retail | 1999 |
| Jessheim Org AS | Hospitality | 2008 |
| Jessheim Panorama AS | Real estate | 2013 |
| Jessheim Pizza AS | Hospitality | 2004 |
| Jessheim Pizza Og Kebab AS | Hospitality | 2021 |
| Jessheim Service AS | Administrative & support | 2026 |
| Jessheim Skorep. Nøkkelservice Og Rens AS | Other services | 2016 |
| Jessheim Solskjerming AS | Wholesale & retail | 2021 |
| Jessheim Specsavers AS | Wholesale & retail | 2013 |
| Jessheim Stasjonsdrift AS | Wholesale & retail | 2019 |
| Jessheim Sør Utvikling AS | Real estate | 2012 |
| Jessheim Takeaway AS | Hospitality | 2010 |
| Jessheim Tannlegesenter AS | Health & social care | 2014 |
| Jessheim Tannlegevakt AS | Health & social care | 2021 |
| Jessheim Tannlegevakt Og Tannklinikk AS | Health & social care | 2017 |
| Jessheim Tele AS | Wholesale & retail | 1997 |
| Jessheim Transport AS | Transport & logistics | 2016 |
| Jessheim VVS & Varmeservice AS | Construction | 2019 |
| Jessheimgruppen AS | Professional & scientific | 2010 |
| Jessheimlegene AS | Health & social care | 2024 |
| Jessheimlogopedene AS | Health & social care | 2020 |
| Jessheimpuls AS | Information & communication | 2018 |
| Jewi Invest AS | Real estate | 2005 |
| Jfne Holding AS | | 2022 |
| JFR Invest AS | | 2021 |
| JK Parkett AS | Construction | 2023 |
| Jkm-Salg AS | Wholesale & retail | 2016 |
| JL Innovation AS | Financial services | 2008 |
| John Henric AS | Wholesale & retail | 2024 |
| Joker'N AS | Real estate | 2018 |
| Jolu Holding AS | | 2026 |
| Jonjon AS | | 2025 |
| Jordbærpikene Jessheim AS | Hospitality | 2008 |
| Jordis AS | Wholesale & retail | 2026 |
| Jostein Dahl Holding AS | Financial services | 2016 |
| Jova Services AS | Administrative & support | 2021 |
| Joyfulcreation AS | Education | 2026 |
| JS Finans AS | Professional & scientific | 2017 |
| JS Øveraas Holding AS | Financial services | 2013 |
| Julius Dahls Vei 3 AS | Real estate | 2022 |
| Jutus Skandinavia AS | Information & communication | 2019 |
| Jølsen Eiendom 2 AS | Real estate | 2020 |
| K by Kaos Jessheim AS | Wholesale & retail | 2019 |