| 55 North Network Limited | Professional & scientific | 2008 |
| A & a Mackay (Builders) Limited | Construction | 2003 |
| A & C Macdonald Ltd | Real estate | 2025 |
| A & R Mechanical Engineering & Recovery Services Ltd | Manufacturing | 2019 |
| A & R Pottinger Ltd | Extraterritorial | 2023 |
| A. M. Harper | Hospitality | 2013 |
| A9 Plumbing Limited | Construction | 2020 |
| ABB Hospitality Ltd | Hospitality | 2026 |
| Achvarasdal Lodges Ltd | Hospitality | 2024 |
| AH (Civil & Structural) Limited | Construction | 2007 |
| AH (Environmental) Ltd | Professional & scientific | 2011 |
| AH (Qatar) Ltd | Professional & scientific | 2011 |
| AH Maritime Limited | Construction | 2007 |
| Alba Renewables Ltd | Agriculture & fishing | 2006 |
| Alien SIM Products Ltd | Manufacturing | 2020 |
| Allan Electrical (Thurso) Ltd | Manufacturing | 2014 |
| AM Project Solutions Ltd | Professional & scientific | 2025 |
| Anderson & Moore Leisure Ltd | Hospitality | 2008 |
| Anderson Refrigeration Ltd | Construction | 2025 |
| Angels' Share Custom Pens Ltd | Extraterritorial | 2016 |
| Arcade Tans & Spaces Ltd | Real estate | 2024 |
| Archway Hospitality Ltd | Hospitality | 2022 |
| As&Cms Limited | Wholesale & retail | 2015 |
| Atomec Consulting Limited | Professional & scientific | 2026 |
| Atomic Engineering Solutions Ltd | Professional & scientific | 2014 |
| Autolux Detailing Solutions Ltd | Construction | 2016 |
| Autoparts of Thurso | Wholesale & retail | 2015 |
| Baillie Wind Farm Community Benefit Fund | Financial services | 2013 |
| Barry Property Limited | Real estate | 2018 |
| Bell's Seafoods Ltd | Wholesale & retail | 2012 |
| Bellshelf AH Limited | Professional & scientific | 2007 |
| BL Mackay Limited | Construction | 2007 |
| Blackheath Operations & Technical Services Ltd | Professional & scientific | 2018 |
| Blackwood Fencing Limited | Administrative & support | 2025 |
| Blackwood Services Ltd | Construction | 2021 |
| Bottle Exchange Ltd | Wholesale & retail | 2021 |
| Bountiful Fishing Limited | Agriculture & fishing | 2024 |
| Boyd Training Limited | Education | 2021 |
| Braemara Limited | Professional & scientific | 1999 |
| Bridgend Health Care Centre Limited | Health & social care | 2017 |
| Broken RAT Games Ltd | Information & communication | 2024 |
| Broubster Consulting Associates Ltd | Professional & scientific | 2023 |
| Burke Motors Ltd | Wholesale & retail | 2020 |
| Buzz Fishing Company Ltd | Agriculture & fishing | 2025 |
| Bydand (Thurso) Limited | Hospitality | 2016 |
| C S Drilling Services Limited | Mining & quarrying | 2007 |
| C. Gunn Electrical Services Ltd | Manufacturing | 2024 |
| Caithness & North Sutherland Fund | Administrative & support | 2011 |
| Caithness Agricultural Society | Arts & recreation | 2006 |
| Caithness and Sutherland Women's AID | Other services | 2007 |
| Caithness Autocross Club Ltd | Arts & recreation | 2015 |
| Caithness Business Fund | Other services | 2013 |
| Caithness Citizens Advice Bureau | Information & communication | 1988 |
| Caithness Counselling Services Ltd | Health & social care | 2014 |
| Caithness Crop Processing Limited | Agriculture & fishing | 1993 |
| Caithness Cuisine -Thurso Limited | Hospitality | 2026 |
| Caithness Cuisine Limited | Hospitality | 2025 |
| Caithness Embroidery & Clothing Printing Ltd | Manufacturing | 2026 |
| Caithness F.M. Limited | Information & communication | 1998 |
| Caithness Investors Ltd | Real estate | 2010 |
| Caithness Osteopathic Services Ltd. | Health & social care | 2016 |
| Caithness Plates Ltd | Wholesale & retail | 2026 |
| Caithness Renewables Ltd | Professional & scientific | 2010 |
| Caithness Scaffolding Contractors Limited | Construction | 1997 |
| Caithness Ventilation Services Ltd | Manufacturing | 2019 |
| Calder Engineering Ltd. | Manufacturing | 1988 |
| Calder Offshore Limited | Manufacturing | 2009 |
| Campbell & Rose Holdings Ltd | Financial services | 2024 |
| Capilla Tapas Limited | Hospitality | 2025 |
| Carmel Herbals Limited | Manufacturing | 1990 |
| Castle and Gardens of MEY Limited | Wholesale & retail | 2003 |
| CCS 2023 Ltd | Hospitality | 2023 |
| Chafar Limited | Professional & scientific | 2026 |
| Charles Sutherland Joinery & Construction | Construction | 2012 |
| Chris's Household Services Ltd | Construction | 2019 |
| Cinematiq Ltd | Information & communication | 2024 |
| CJA Properties Ltd | Real estate | 2026 |
| Clairdonhill Fishing Ltd | Agriculture & fishing | 2025 |
| Clean Bees Ltd | Administrative & support | 2016 |
| Clean Crazy Ltd | Administrative & support | 2015 |
| CLM Agri Ltd | Wholesale & retail | 2024 |
| Cloudalive Limited | Information & communication | 2019 |
| CNC Hotels Ltd | Hospitality | 2019 |
| Coghill Technical Services Limited | Professional & scientific | 2021 |
| Collier Events Ltd | Hospitality | 2018 |
| Commercial Hotel (Thurso) Ltd | Hospitality | 2011 |
| Compucloud Ltd | Information & communication | 2011 |
| Contec Design Services Ltd | Administrative & support | 2008 |
| Corcoran Property Sales Ltd | Real estate | 2023 |
| Couthie Cafe Ltd | Hospitality | 2024 |
| Cowan Plant Strathy Limited | Construction | 2013 |
| Cowan Timber Ltd | Wholesale & retail | 2021 |
| Craigie Joinery Ltd | Construction | 2015 |
| Creativity in Care CIC | Education | 2012 |
| CRL Services Ltd | Construction | 2024 |
| CRL Supplies Ltd | Manufacturing | 2025 |
| Crosskirk Energy Limited | Financial services | 2021 |
| Cuanadhair Ltd | Hospitality | 2026 |
| Curocom Ltd | Professional & scientific | 2024 |
| Cyber Security Scotland | Information & communication | 2016 |