| KJR Waste Ltd | Wakefield | 2022 |
| KKL Management | Leeds | 2011 |
| Kl-Drainage Ltd | Aberdeen | 2025 |
| KLA Ventures Limited | Hildenborough | 2014 |
| Klaisen Ltd | Doncaster | 2018 |
| Klean AF Ltd | Harlow | 2025 |
| Klear + Move Limited | Derby | 2025 |
| Klear-It Limited | Dalkeith | 2000 |
| Klearco Ltd | Droitwich | 2026 |
| Klearwayjunk Junk Ltd | Glasgow | 2026 |
| Kleen Experts Ltd | London | 2025 |
| Kleerkut Limited | Glasgow | 2006 |
| Klimate Labs Ltd | Coalville | 2018 |
| KLM Drainage Services Ltd | Willenhall | 2025 |
| KLM Waste&Removals Ltd | Keighley | 2024 |
| KLN Recycling Ltd | Colindale | 2020 |
| Klotta Ltd | Leeds | 2025 |
| KM Eco Ltd | Hertford | 2018 |
| KM Environmental Limited | St. Asaph | 2003 |
| KM Property Services (Southern) Ltd | Horsham | 2024 |
| KM Waste and Recycling Ltd | Gateshead | 2025 |
| KMC Waste Transfer Station Ltd | Sevenoaks | 2025 |
| KMF Drainage Ltd | Chester | 2005 |
| KMG Holdings Ltd | Swansea | 2018 |
| KMK Metals Recycling Limited | Newry | 2025 |
| Knaresborough Water Ltd | Milton Keynes | 2025 |
| Knbl Services Limited | Airdrie | 2002 |
| Knightgrade Limited | Tetbury | 1973 |
| Knights Asbestos Ltd | West Molesey | 2025 |
| Knights Fire and Security Ltd | Coventry | 2023 |
| Knights of Oxney Building Contractors Ltd | Tonbridge | 2020 |
| Knightswood Recycling Limited | Manchester | 2025 |
| Kniveton (UK) Limited | Sheffield | 1998 |
| KNJ Roofing Limited | Wimborne | 2018 |
| Knockothie Environmental Ltd | Ellon | 2015 |
| Knockout Waste Control Ltd | Orpington | 2019 |
| Knotweed Doctor Limited | Chester | 2018 |
| Knotweed Treatments Limited | Bury St. Edmunds | 2019 |
| Know HOW Today Limited | Colchester | 2018 |
| Knowab Grab Hire Ltd | Coulsdon | 2025 |
| Knowab Ltd | Sutton | 2015 |
| Knox Natural Resources Ltd | Reigate | 2026 |
| KNP Drainage Ltd | Sittingbourne | 2026 |
| KNR Group - Waste Management Ltd | Rainham | 2024 |
| KNS OIL Limited | London | 2025 |
| KO Drainage Limited | Glasgow | 2023 |
| KO Plant Operators Ltd | Bishop'S Stortford | 2024 |
| KO Removals and Maintenance Limited | Bromsgrove | 2023 |
| Kobell Fluid Technology Limited | Kenilworth | 2007 |
| Kodiva Ltd | Feltham | 2017 |
| Kodonidis Cars Ltd | Motherwell | 2024 |
| Kofy Clearance and Waste Management Limited | South Croydon | 2026 |
| Koko OIL Ltd | Newport | 2021 |
| Kolev&Co Limited | London | 2022 |
| Kolina Limited | Harrogate | 2008 |
| Komi Cars and Parts Ltd | Hayes | 2023 |
| Komline-Sanderson Ltd | Horsham | 1992 |
| Konclude AWS Limited | Esher | 2003 |
| Konclude Environmental Ltd | Esher | 2008 |
| Konclude Environmental Materials Management Limited | Esher | 2009 |
| Kong Waste Management Limited | Glasgow | 2023 |
| Konnect Water Solutions Ltd | Milton Keynes | 2018 |
| Koonkeel Ltd | Liverpool | 2004 |
| Koppers Landfill Limited | Kirkstall | 2020 |
| Korfoe Environment Co., Ltd | Coventry | 2022 |
| Korona London Waste Ltd | London | 2019 |
| Korona Waste London Ltd | London | 2026 |
| Kosamo Deepclean Ltd | Coventry | 2023 |
| Kost Corporation Ltd | London | 2021 |
| Koster Group Limited | Ramsgate | 2026 |
| Kostime Ltd | London | 2018 |
| KPH Grab Hire Ltd | Aberdeen | 2022 |
| KPM Removals Ltd | Poole | 2025 |
| KPS Composting Services Limited | Haywards Heath | 2000 |
| KPS Recycling Limited | Scaynes Hill | 2009 |
| Kpse Construction Ltd | London | 2023 |
| KPT Hatton Gardens Ltd | Liverpool | 2018 |
| KR BON Reduction Ltd | Ellon | 2023 |
| KR Clearance Limited | Hornchurch | 2023 |
| KR Trading Limited | Barton-Upon-Humber | 2025 |
| Kraken Ltd | Wigan | 2023 |
| Kris Clearance Limited | Thornton Heath | 2016 |
| Kristal Koko Ltd | Arbroath | 2022 |
| KRS Recycling Limited | Kidderminster | 2014 |
| Krutak Ltd | Derby | 2018 |
| Kruze Ltd | Leeds | 2025 |
| KSA Green Solutions Ltd | Bedford | 2025 |
| KSB Waste Management Limited | Pevensey Bay | 2023 |
| KSD (Contracts) Limited | Nuneaton | 1992 |
| KSD Environmental Services Limited | Bexhill On Sea | 2004 |
| KSD Recycled Aggregates Limited | Coventry | 2001 |
| KSK Mainlaying Limited | Norwich | 2011 |
| Kstar Removals Limited | Hull | 2025 |
| KT Building Limited | Worthing | 2019 |
| KT Pumps Ltd | Thetford | 2026 |
| KT Recycling Limited | Preston | 2016 |
| KT Recycling Solutions Ltd | Altrincham | 2018 |
| KT Skip Hire Limited | Whitehaven | 2024 |
| KT Waste Management NE Ltd | Stanley | 2026 |
| KT4 Hire Ltd | Birmingham | 2011 |