| K Thompson Ltd | Administrative & support | 2023 |
| K V Computer Services Limited | Information & communication | 1993 |
| K.A.M Cleaning Limited | Administrative & support | 2025 |
| K.A.S Rentals Ltd | Real estate | 2024 |
| K.M. FRY Limited | Real estate | 2006 |
| Kabstrong Limited | Health & social care | 2016 |
| Kace Recycling Ltd | Water & waste | 2023 |
| Kane Decorators Limited | Construction | 2022 |
| Kane White Ltd | Construction | 2025 |
| Kaths Kafe Ltd | Hospitality | 2025 |
| Katy Melling Photography Ltd | Professional & scientific | 2024 |
| KBC Creations Ltd | Information & communication | 2026 |
| KBS Hair NE Ltd | Other services | 2018 |
| KCL Logistics Limited | Transport & logistics | 2011 |
| Keith Pattinson Limited | Real estate | 1987 |
| Kennedy's Office Limited | Arts & recreation | 2012 |
| Kensho Karate Limited | Arts & recreation | 2019 |
| Khushnav Ltd | Wholesale & retail | 2020 |
| Kieron Robert John Dunn Ltd | Professional & scientific | 2024 |
| Kikihair Limited | Other services | 2019 |
| Kinetix Bounce Ltd | Arts & recreation | 2026 |
| Kingston Services (2015) Ltd | Administrative & support | 2015 |
| Kirk Field Ulgham Caravan Park Ltd | Hospitality | 2024 |
| Kitchen Magic SR4 Ltd | Wholesale & retail | 2011 |
| Kitsune Digital Ltd | Information & communication | 2020 |
| Kixx North East Limited | Education | 2019 |
| KJ Data Training Ltd | Education | 2025 |
| KJB Fit-Out UK Ltd | Construction | 2022 |
| KK Properties (NE) Ltd | Real estate | 2025 |
| KL (NE) Ltd. | Hospitality | 2018 |
| Kleoma Place Limited | Real estate | 2026 |
| KML Kare Limited | Health & social care | 2021 |
| KMT Transport Ltd | Transport & logistics | 2025 |
| KNI Solutions Ltd | Professional & scientific | 2019 |
| Know & Thrive Initiative CIC | Health & social care | 2026 |
| Komodo Projects Ltd | Real estate | 2019 |
| Konnect Audio CIC | Arts & recreation | 2019 |
| Krleisure Ltd | Hospitality | 2022 |
| Krystal Technology UK Limited | Manufacturing | 1998 |
| KS Pipe Services Ltd | Administrative & support | 2017 |
| KT2 HV Ltd | Energy | 2024 |
| Kunekt Limited | Professional & scientific | 2018 |
| KW Aesthetics & Skin Ltd | Other services | 2026 |
| L & G Brickwork Specialists Limited | Construction | 2014 |
| L & G Building & Construction Ltd | Construction | 2025 |
| L & L Property Services Ltd | Real estate | 2020 |
| L B Roofing & Property Maintenance Ltd | Construction | 2026 |
| L D Property Solutions Ltd | Manufacturing | 2025 |
| L Fergusson Builders Limited | Construction | 2019 |
| L S Piping Ltd | Construction | 2026 |
| LA Florenta Limited | Hospitality | 2024 |
| Lakes Heating Ltd | Construction | 2025 |
| Land and Sea Projects Limited | Manufacturing | 2017 |
| Landino Construction Ltd | Construction | 2024 |
| Landmark Tiling Contractors Limited | Construction | 2015 |
| Lanndman Ltd | Administrative & support | 2007 |
| Lantern on the Tyne Cafe Ltd | Hospitality | 2025 |
| LAP Family Ltd | Other services | 2024 |
| Lasgo Limited | Administrative & support | 2006 |
| LD Tattoo Limited | Other services | 2023 |
| Leia Star Scott - Concept Arts Ltd | Arts & recreation | 2022 |
| Lemonstockuk Ltd | Wholesale & retail | 2023 |
| LET Elite UK Limited | Real estate | 2024 |
| Letsmove Residential Limited | Real estate | 2011 |
| Level Flooring North East Limited | Construction | 2011 |
| Lewis Property Vision Ltd | Real estate | 2025 |
| LGF Power Limited | Professional & scientific | 2025 |
| Liam Dodds Ltd | Education | 2023 |
| Liam Tully Lighting Design Ltd | Arts & recreation | 2018 |
| Lifelong Ability North East (Lane) Ltd | Health & social care | 2023 |
| Lifestyle Express Wallsend Ltd | Wholesale & retail | 2026 |
| Lifetime Flooring UK Limited | Construction | 2013 |
| Light Dental Ltd | Health & social care | 2025 |
| Lightfoot Consultancy Limited | Professional & scientific | 2025 |
| Lime Street Developments N.E. Limited | Administrative & support | 2020 |
| Limitless Construction Consultants Ltd | Professional & scientific | 2020 |
| Limitless Marketing Group Limited | Wholesale & retail | 2020 |
| Liquid Joy Ltd | Wholesale & retail | 2023 |
| Little Robot CIC | Education | 2025 |
| Little Sunshine Childcare Ltd | Health & social care | 2019 |
| Little Sunshine Role Play & Cafe Ltd | Hospitality | 2024 |
| Liya Software Solution Ltd | Information & communication | 2020 |
| LJ Home Care Support Ltd | Health & social care | 2025 |
| LJR Production Ltd | Other services | 2016 |
| LK Real Estate Ltd | Real estate | 2024 |
| Lklc Properties Ltd | Real estate | 2025 |
| LLF (NE) Ltd | Hospitality | 2023 |
| LM Enterprise North East Limited | Arts & recreation | 2022 |
| LMB Education Services Ltd | Administrative & support | 2017 |
| LMR Consultants Ltd | Professional & scientific | 2019 |
| Lomax Training Services Limited | Education | 2001 |
| Longsands Leisure Group Limited | Hospitality | 2017 |
| Loot Boss Ltd | Wholesale & retail | 2022 |
| Lopez Electrical Ltd | Mining & quarrying | 2011 |
| Louise Walker Limited | Health & social care | 2023 |
| Louvero Ltd | Manufacturing | 2026 |
| LR Waste Disposal Limited | Water & waste | 2025 |
| Lrgtrading Ltd | Wholesale & retail | 2025 |
| LT Coatings Ltd | Construction | 2025 |
| Lucamy Properties Limited | Real estate | 2016 |