| Immerse Hebrides Ltd | Transport & logistics | 2021 |
| Indecx Ltd | Information & communication | 2026 |
| Independent Mortgage Shop Limited | Financial services | 2017 |
| Industry Ltd | Extraterritorial | 2024 |
| Interchange Ltd | Information & communication | 2026 |
| IOL Engineering Services Ltd | Professional & scientific | 2022 |
| Iomairt Engineering Ltd | Professional & scientific | 2019 |
| Ipxid Ltd | Administrative & support | 2020 |
| Irina Rentals Ltd | Real estate | 2020 |
| Island Sweet Events Ltd | Hospitality | 2023 |
| Island Welding Services Ltd | Professional & scientific | 2022 |
| Isle Inspire Limited | Wholesale & retail | 2019 |
| Isle of Lewis Glamping Ltd | Hospitality | 2024 |
| IT Wright Limited | Information & communication | 2015 |
| J H M Financial Ltd | Financial services | 2007 |
| J. & E. Macleod, Limited | Administrative & support | 1959 |
| JDB Haulage Ltd | Transport & logistics | 2025 |
| JEB Properties Ltd | Real estate | 2020 |
| John Maciver and Sons Limited | Administrative & support | 2004 |
| JPW Chem Pro ENG Limited | Professional & scientific | 2021 |
| KBM Contracts Limited | Mining & quarrying | 2018 |
| Kenman Holdings Limited | Professional & scientific | 1988 |
| Kenneth Mackenzie Limited | Manufacturing | 1970 |
| Keose and Glebe Community Association | Administrative & support | 2002 |
| Keose Glebe Estate Limited | Other services | 2015 |
| Kevin Macdonald Electrical Services Ltd | Manufacturing | 2019 |
| Kilbride Electrical Ltd | Construction | 2021 |
| Kinloch Construction Limited | Construction | 2011 |
| Kirklea Cottages Limited | Hospitality | 2003 |
| KLJ Holdings Limited | Financial services | 2025 |
| Kscs (Stornoway) Ltd | Administrative & support | 2012 |
| L&L Bistros Ltd | Hospitality | 2018 |
| Laird Inspection Limited | Mining & quarrying | 2011 |
| Leveret West Ltd | Professional & scientific | 2022 |
| Lewis & Harris Auction Mart (2005) Limited | Wholesale & retail | 2005 |
| Lewis and Harris Scallops Ltd | Agriculture & fishing | 2020 |
| Lewis Builders Limited | Construction | 1989 |
| Lewis Car Club | Arts & recreation | 2001 |
| Lewis Island Crofters, Limited | Other services | 1923 |
| Lewis Macleod Fencing Limited | Construction | 2024 |
| Lewis Salmon Limited | Real estate | 1984 |
| Lewis Tyre Service Limited | Extraterritorial | 1986 |
| LFD Marine Contractors Limited | Professional & scientific | 2024 |
| Lighting Electrical Limited | Wholesale & retail | 2000 |
| Living Well Clinic Ltd | Health & social care | 2024 |
| Loch Carloway Shellfish Limited | Manufacturing | 2021 |
| Lochs Diving Services Limited | Professional & scientific | 2005 |
| Lochs Motor Transport Limited | Transport & logistics | 1947 |
| Long Island Rural Trust | Real estate | 2005 |
| LÁN Blast Ltd | Hospitality | 2022 |
| M a Murray Consulting Limited | Professional & scientific | 2007 |
| MAC Rigging Services Ltd | Mining & quarrying | 2018 |
| Mac's SY Limited | Mining & quarrying | 2018 |
| Macaskill Fuels Limited | Wholesale & retail | 2002 |
| Macaskills Home Store Limited | Wholesale & retail | 2001 |
| Macbrew Ltd | Manufacturing | 2025 |
| Macdonald Coaches Limited | Transport & logistics | 2007 |
| Macdonald Property Hebrides Ltd | Real estate | 2025 |
| Maciver Consultancy Services Limited | Construction | 2007 |
| Maciver Ltd | Construction | 2018 |
| Mackay & Mackay (Holdings) Limited | Financial services | 2003 |
| Mackay & Mackay Limited | Wholesale & retail | 1984 |
| Mackay Investments Limited | Real estate | 1999 |
| Mackay Properties Limited | Real estate | 1992 |
| Mackay Transport Services Ltd | Transport & logistics | 2026 |
| Mackenzie Holdings Limited | Wholesale & retail | 1988 |
| Maclean Mair Nicolson & Co. Limited | Wholesale & retail | 1978 |
| Maclennan Contractors Limited | Professional & scientific | 2014 |
| Macleod Contractors Point Limited | Agriculture & fishing | 2019 |
| Macleod Garages Ltd | Transport & logistics | 2006 |
| Macleod Heating Services Limited | Construction | 2025 |
| Macleod INS Services Limited | Financial services | 2015 |
| Macleod Services Ltd | Manufacturing | 2025 |
| Macleod Services Stornoway Ltd | Transport & logistics | 2024 |
| Macmillan Engineering Ltd | Professional & scientific | 2006 |
| Macmillan Rigging and Lifting Ltd | Construction | 2024 |
| Macritchie Fishing Company Limited | Agriculture & fishing | 2022 |
| Maireann Consulting Ltd | Administrative & support | 2016 |
| Malcolm Mackenzie and Co Limited | Manufacturing | 1979 |
| Mangersta Limited | Professional & scientific | 2006 |
| Mann Judd Gordon Ltd | Professional & scientific | 2008 |
| Manor Hotel (Stornoway) Limited | Hospitality | 1970 |
| Maridon Marine Engineering Limited | Professional & scientific | 2013 |
| Martins Memorials Limited | Manufacturing | 2016 |
| Marvig Marine Surveys Limited | Professional & scientific | 2020 |
| Marvig Pier Users Group | Administrative & support | 2001 |
| Mask Property Developments Limited | Financial services | 2016 |
| Mast-Ard Studio Limited | Information & communication | 2018 |
| MCS Technical Ltd | Professional & scientific | 2015 |
| Mepg Ltd | Construction | 2020 |
| Miavaig Bay Mussels Limited | Wholesale & retail | 1999 |
| Millar Rope Access Ltd | Administrative & support | 2007 |
| Mimec Ltd | Real estate | 2002 |
| Miolaid Management Limited | Professional & scientific | 2011 |
| Miver Ltd | Construction | 2025 |
| Modern Homes Store Ltd | Wholesale & retail | 2023 |
| Moja Limited | Information & communication | 2005 |
| Morr Group Limited | Other services | 2026 |
| Morr Industrial Supplies Ltd | Other services | 2025 |
| MT Group (Scotland) Ltd | Manufacturing | 2022 |