| John and LEE Properties Ltd | Real estate | 2025 |
| John Duff (Joiners) Ltd. | Construction | 2003 |
| John Dunbar & Company Limited | Professional & scientific | 1927 |
| John Lindsay (Dumbuck) Limited | Wholesale & retail | 1965 |
| Joseph Harkom & SON Gunmakers Limited | Manufacturing | 2025 |
| Jowa Engineering and Safety Ltd | Professional & scientific | 2024 |
| JPS Structures Limited | Construction | 2021 |
| JRC Property Services Ltd | Real estate | 2026 |
| JRS Engineering (SCO) Ltd | Professional & scientific | 2026 |
| Jskhaira Ltd | Real estate | 2024 |
| Juice Bar Dumbarton Ltd | Hospitality | 2018 |
| JW Roofing & Building Ltd | Construction | 2026 |
| K.Donnelly Hydrographic Support Ltd | Administrative & support | 2017 |
| K.Liddell Plumbing & Heating Ltd | Construction | 2022 |
| Kalos Consulting Ltd | Professional & scientific | 2023 |
| Kaney Renovations Ltd | Construction | 2020 |
| Kapama Limited | Administrative & support | 2012 |
| Kath-Maur Limited | Real estate | 2022 |
| KDR Pubs Limited | Hospitality | 2017 |
| Kilmardinny 70 Limited | Financial services | 2022 |
| Kinglas Property Consultants Limited | Real estate | 2017 |
| Kjjm Rail Ltd. | Construction | 2017 |
| KM Signalling Ltd | Construction | 2022 |
| KM Signalling Maintenance Ltd | Construction | 2025 |
| Kmag Lifting Ltd | Administrative & support | 2017 |
| Knight Errand Ltd | Transport & logistics | 2008 |
| KNY Properties Limited | Real estate | 2024 |
| Koniarik Construction Ltd | Construction | 2025 |
| KR Quality Consultants Ltd | Professional & scientific | 2026 |
| KRP Accountants Ltd. | Professional & scientific | 2012 |
| KRP Investments Ltd | Real estate | 2019 |
| KWW Ltd | Professional & scientific | 2020 |
| Kylo Ltd | Education | 2025 |
| Kyndl Fyre Ltd | Wholesale & retail | 2025 |
| L & M IT Services Limited | Information & communication | 2025 |
| L&C Eats Ltd | Hospitality | 2020 |
| Lady C Boutique Ltd | Wholesale & retail | 2021 |
| Larive Ltd | Administrative & support | 2015 |
| Laser Room HQ Ltd | Other services | 2025 |
| Lawson & Smith Limited | Professional & scientific | 1939 |
| Lennox Bar Dunbartonshire Ltd | Hospitality | 2015 |
| Lennox Brewery Limited | Manufacturing | 2017 |
| Leven Holistics Limited | Other services | 2023 |
| Leven Media Ltd | Information & communication | 2015 |
| Levengrove Dental Limited | Real estate | 2006 |
| Levengrove Properties Ltd | Real estate | 2025 |
| Lewfrey Ltd | Professional & scientific | 2018 |
| Liam Henry Joinery Ltd | Construction | 2025 |
| Lily Nails & Beauty Ltd | Other services | 2023 |
| Little Kickers Nursery Ltd | Health & social care | 2025 |
| Lizzies Sparkling Cleaning Services Ltd | Administrative & support | 2019 |
| Lloyd Energy & Engineering Limited | Manufacturing | 2013 |
| Lloyd Technology Ltd | Information & communication | 2012 |
| Lmgs Bites Limited | Hospitality | 2026 |
| Local Trades Property Maintenance Ltd | Construction | 2006 |
| Loch Lomond House Buyers Ltd | Real estate | 2021 |
| Loch Lomond TV C.I.C. | Information & communication | 2021 |
| Loch Lomond Wakeboard Ltd | Arts & recreation | 2009 |
| Lochside Campers Ltd | Administrative & support | 2022 |
| Lockstone Limited | Professional & scientific | 1995 |
| Lodestone Creative CIC | Education | 2016 |
| Lodestone Workspaces Ltd | Real estate | 2023 |
| Lomond & Clyde Taxis Limited | Transport & logistics | 2025 |
| Lomond Adhd Services C.I.C. | Education | 2025 |
| Lomond and Clyde Care & Repair Limited | Other services | 2002 |
| Lomond Business Associates Limited | Administrative & support | 2025 |
| Lomond Chippy Ltd | Hospitality | 2023 |
| Lomond Contracting Ltd | Construction | 2024 |
| Lomond Home Improvements Ltd | Construction | 2025 |
| Lomond Radio Ltd | Information & communication | 2021 |
| Lomond Sports Bar Ltd | Administrative & support | 2026 |
| Lomond Sports Management Ltd | Arts & recreation | 2025 |
| Lomond Taxis Ltd | Transport & logistics | 2025 |
| Long John Distilleries Limited | Professional & scientific | 1927 |
| Longmorn Distilleries Limited (the) | Professional & scientific | 1897 |
| Lookumades Limited | Hospitality | 2026 |
| Lsmack Ltd | Real estate | 2025 |
| Lubiewski Joinery Services Ltd | Construction | 2025 |
| Luge Limited | Real estate | 2001 |
| LUX Towers Limited | Real estate | 2025 |
| M E Oriental Trading Ltd | Wholesale & retail | 2017 |
| M Rodgers Couriers Ltd | Transport & logistics | 2025 |
| M&R Bodrum Ltd. | Other services | 2015 |
| M90 Auto Salvage Ltd | Wholesale & retail | 2021 |
| Mackinlay & Mitchell Gunmakers Ltd | Manufacturing | 2026 |
| Magical Maids Ltd | Administrative & support | 2025 |
| MAR Traders Limited | Wholesale & retail | 2017 |
| Marblac Ltd | Real estate | 2023 |
| Mardanscotia Ltd | Households | 2020 |
| Marjor Hotels Limited | Hospitality | 1995 |
| Markt 7889 Ltd | Wholesale & retail | 2017 |
| Mateen Hamza Ltd | Other services | 2017 |
| Mathieson Group Limited | Construction | 2025 |
| Matty Gemmell Property Ltd | Households | 2026 |
| MAV Technical Solutions Ltd | Energy | 2024 |
| MB Property Scotland Ltd. | Real estate | 2021 |
| MBE Dental and Medical Ltd | Health & social care | 2022 |
| MBE Travel Ltd | Administrative & support | 2024 |
| MC Beauty Products Ltd | Wholesale & retail | 2018 |
| Mcaulay Fabrication Ltd | Manufacturing | 2023 |