| Jorgensen Craik Properties Ltd | Real estate | 2024 |
| Joro Industrial Limited | Administrative & support | 2022 |
| Joseph Turbitt Electricals Limited | Construction | 2016 |
| Jova Property Ltd | Real estate | 2024 |
| JOW Logistics Ltd | Transport & logistics | 2025 |
| JP Furnishings Ltd | Wholesale & retail | 2023 |
| JP Rigging Lifting and Rail Limited | Manufacturing | 2025 |
| Jpaitken Investments Ltd | Financial services | 2022 |
| Jrch Ltd | Real estate | 2020 |
| JRW Studio Limited | Information & communication | 2017 |
| JT Clarity Group Ltd | Other services | 2025 |
| JT Mortgage Services Ltd | Financial services | 2025 |
| Judges Drive Ltd | Real estate | 2025 |
| Jule-Tech Ltd | Other services | 2015 |
| JWE Projects Ltd | Other services | 2016 |
| K a D Contractors Limited | Energy | 2016 |
| K a Rope Access Ltd | Construction | 2019 |
| K and G Grewal Ltd | Real estate | 2025 |
| K H PMC Limited | Other services | 2014 |
| K House Properties Ltd | Real estate | 2020 |
| K M Coatings North East Ltd | Construction | 2019 |
| K Stelling Limited | Construction | 2018 |
| K.L.L Solutons Ltd | Manufacturing | 2012 |
| K.W. Reader & Sons Limited | Wholesale & retail | 1992 |
| K2 HSE Management Ltd | Construction | 2012 |
| KAI Williamson-Jones Ltd | Manufacturing | 2026 |
| Kailash Lettings Limited | Real estate | 2025 |
| Kalboa Properties Ltd | Real estate | 2025 |
| Kalma Life Ltd | Education | 2014 |
| Karumu KAI Ltd | Hospitality | 2026 |
| Kate Kavanagh Consulting Ltd | Professional & scientific | 2025 |
| Katy SUE Designs Limited | Manufacturing | 2004 |
| Katy SUE International Limited | Professional & scientific | 2016 |
| Kaur Pharma Limited | Wholesale & retail | 2016 |
| KB Couriers Limited | Transport & logistics | 2011 |
| KB Offshore Ltd | Professional & scientific | 2025 |
| Kbbi Ltd | Manufacturing | 2017 |
| KBG Plastering Ltd | Construction | 2026 |
| KD Fibre Optics Limited | Construction | 2024 |
| Keithharra ENG Ltd | Construction | 2012 |
| Kenneth Raymond Ltd | Professional & scientific | 2014 |
| Keston Inspection Services Limited | Professional & scientific | 2012 |
| Ketchup Mustard & Onion Limited | Transport & logistics | 2016 |
| Kevcad V5 Services Limited | Administrative & support | 2016 |
| Key Community | Education | 2004 |
| Key Subject Tuition Ltd | Education | 2020 |
| Keyworth Cottages Limited | Real estate | 2018 |
| KFR Consulting Services Limited | Professional & scientific | 2026 |
| KG Power Services Ltd | Professional & scientific | 2026 |
| KI Commercial Services Limited | Construction | 2015 |
| Kielder Close RTM Company Limited | Real estate | 2021 |
| Kindergarten Dog Day Care Ltd | Agriculture & fishing | 2025 |
| Kinetic Records Limited | Hospitality | 2024 |
| Kirby College Management Company Limited | Real estate | 2010 |
| Kirsten Woodworks Limited | Other services | 2014 |
| Kirton Construction Services Limited | Construction | 2023 |
| KIS Sales & Lettings (North Shields) Limited | Real estate | 2010 |
| Kiss Mist Limited | Manufacturing | 2025 |
| Kitchencore Ltd | Professional & scientific | 2011 |
| Kitchens 2 Your Door Limited | Other services | 2011 |
| KIZ Hair WIZ Ltd | Other services | 2026 |
| Kj's Spray Solutions Ltd | Construction | 2025 |
| KJB R/A Coating Inspection Ltd | Professional & scientific | 2018 |
| KJS Events Limited | Hospitality | 2024 |
| Kkal Ltd | Wholesale & retail | 2024 |
| KLM Electrical & Renewables Ltd | Construction | 2025 |
| KLM Tiles Ltd | Wholesale & retail | 2025 |
| Klpr Arts Limited | Manufacturing | 2025 |
| KLR Plumbing, Heating and GAS Services Ltd | Other services | 2017 |
| KLS Electrical Services Ltd | Manufacturing | 2019 |
| KMC Access Limited | Other services | 2010 |
| Kmjpearson Ltd | Construction | 2025 |
| Knit & Nest Limited | Wholesale & retail | 2025 |
| KOB Controls Limited | Mining & quarrying | 2015 |
| Kobemm Limited | Real estate | 2024 |
| KP Roofing Ltd | Construction | 2021 |
| KP Simpson South Shields Ltd | Professional & scientific | 2021 |
| Kp.Accesssolutions Ltd | Manufacturing | 2017 |
| Kpaccessltd Ltd | Manufacturing | 2026 |
| KPC Events Limited | Hospitality | 2024 |
| Kplp Properties Ltd | Real estate | 2020 |
| Kraven Coffee Company Limited | Hospitality | 2024 |
| Krcl Limited | Construction | 2012 |
| Kriegelewicz Medical Ltd | Health & social care | 2011 |
| Krishna (South Shields) Limited | Hospitality | 2025 |
| KRS Scaffolding Services Ltd | Construction | 2018 |
| KS Coaching for Kids Ltd | Education | 2024 |
| KSJ Painting Ltd | Construction | 2026 |
| KT Autos Ltd | Wholesale & retail | 2025 |
| KT Stone Masonry Ltd | Manufacturing | 2023 |
| Kuei-Ling Events and Apparel Limited | Other services | 2022 |
| Kuei-Ling Martial Arts and Fitness Academy Ltd | Arts & recreation | 2019 |
| Kuhadiya Consultants Ltd | Wholesale & retail | 2014 |
| KW Safety Ltd | Professional & scientific | 2015 |
| Kyron Limited | Hospitality | 2025 |
| L & K Safety Solutions Ltd | Construction | 2025 |
| L & N Abseilers Ltd | Construction | 2012 |
| L C Brews Ltd | Administrative & support | 2025 |
| L H Services N E Limited | Hospitality | 2013 |
| L J Project Services (Tyneside) Ltd | Professional & scientific | 2011 |