| Skills 4 Limited | Education | 2006 |
| Skills 4 Trustees Limited | Administrative & support | 2024 |
| Skillslife Limited | Real estate | 2015 |
| Skin Cell Labs Limited | Manufacturing | 2017 |
| Skin Deep (Leeds) Ltd | Other services | 2006 |
| Sleeves UP Marketing Ltd | Professional & scientific | 2023 |
| Slixir Ltd | Wholesale & retail | 2015 |
| Sloane Limited | Extraterritorial | 2004 |
| SLP Homes Ltd | Real estate | 2023 |
| Smarden Thoroughbreds LLP | | 2021 |
| Smart Maintenance Strategies Ltd | Professional & scientific | 2021 |
| Smart Online Design Limited | Information & communication | 2010 |
| Smart TAG Ltd | Information & communication | 2019 |
| Smartdog Digital Limited | Administrative & support | 2010 |
| SMB Investments Limited | Real estate | 2013 |
| Smile Denture Centres Ltd | Health & social care | 2017 |
| Smithfield Options Limited | Real estate | 2017 |
| Smjd Limited | Real estate | 2019 |
| SMP Headingley Limited | Real estate | 2017 |
| SMP Rentals Limited | Real estate | 2024 |
| Snap XYZ Ltd | Wholesale & retail | 2024 |
| Soccer & Study UK Limited | Arts & recreation | 2020 |
| Social Edge Limited | Information & communication | 2015 |
| Softay Ltd | Financial services | 2022 |
| Software Contractors Ltd | Information & communication | 2022 |
| Soji Systems Limited | Construction | 2004 |
| Solar Site Systems Group Limited | Real estate | 2024 |
| Solar Site Systems Limited | Construction | 2019 |
| Solarfloatuk Ltd | Energy | 2026 |
| Solution Focused Trainers C.I.C. | Other services | 2011 |
| Somac Consultancy Limited | Professional & scientific | 2016 |
| Somerforde Care Limited | Health & social care | 2009 |
| Somerforde Ltd | Health & social care | 2005 |
| Somerforde TOO Ltd | Health & social care | 2022 |
| Somheb Ltd | Hospitality | 2024 |
| Soreacs Ltd | Professional & scientific | 2022 |
| Sorkin Limited | Real estate | 1961 |
| Sotilly Ltd | Professional & scientific | 2023 |
| Soul Kitchen North Ltd | Hospitality | 2026 |
| Sound Foresight Technology Limited | Manufacturing | 2010 |
| Southwood Pubs Ltd | Hospitality | 2026 |
| Spa Casting and Process Consultants Limited | Professional & scientific | 2013 |
| Spa Holdings Limited | Real estate | 2016 |
| Spa Print Services Ltd | Professional & scientific | 2025 |
| Spacebind Ltd | Extraterritorial | 2024 |
| SPC Medical Ltd | Health & social care | 2022 |
| Speedmaster Limited | Wholesale & retail | 2010 |
| Spherix Limited | Professional & scientific | 2013 |
| Sphynx Design Limited | Information & communication | 2010 |
| SPJ Development Services Limited | Professional & scientific | 2020 |
| Spofforth Properties Limited | Real estate | 2017 |
| Spoke Property Limited | Real estate | 2022 |
| Sport Science Solutions Limited | Other services | 2006 |
| Springbok Developments Ltd | Construction | 2024 |
| SRC (Boston Spa) Consultancy Limited | Professional & scientific | 2014 |
| SRC Construction and Paving Ltd | Construction | 2002 |
| SRG Developments Limited | Real estate | 1972 |
| SSS Rallysport Ltd | Wholesale & retail | 2022 |
| ST Roberts Homes (Westgate) Limited | Construction | 2020 |
| ST Roberts Homes Ltd | Real estate | 2001 |
| Stacey Baker Development Limited | Administrative & support | 2014 |
| Stacey Howe Limited | Information & communication | 2011 |
| Stafford Hall Ltd | Wholesale & retail | 2012 |
| Staphyt Ltd | Professional & scientific | 1983 |
| Station Garage Flaxton Limited | Wholesale & retail | 2013 |
| Steadfast Estates Limited | Real estate | 2016 |
| Steel Frame Construction Ltd | Construction | 2017 |
| Stef's Pet Pantry Limited | Wholesale & retail | 2016 |
| Stefan Kusinski Consulting Limited | Information & communication | 2003 |
| Stephen Weets Building and Joinery Ltd | Construction | 2019 |
| Stephen Wilson Design Limited | Information & communication | 2012 |
| Steppingstone Professional Services Limited | Information & communication | 2011 |
| Sterilab Services Ltd | Manufacturing | 2021 |
| Steve Ltd | Financial services | 2000 |
| Stirling 44 Limited | Financial services | 2025 |
| Stirling 722 LLP | | 2018 |
| Stirling 722 SPV1 Ltd | Real estate | 2025 |
| Stirling 722 SPV2 Ltd | Real estate | 2025 |
| Stirling Aviation Properties LLP | | 2005 |
| Stirling Investment Properties LLP | | 2004 |
| Stirling Investments (Sheffield) LLP | | 2004 |
| Stirling Investments Limited | Real estate | 2002 |
| Stirling Partners Real Estate LLP | | 2013 |
| Stirling Properties (Leeds NO.1) LLP | | 2004 |
| Stirling Properties (Leeds NO.2) LLP | | 2005 |
| Stirling Properties (Leeds NO.3) LLP | | 2005 |
| Stirling Properties (Leeds NO.4) LLP | | 2006 |
| Stirling Properties (Leeds NO.5) Limited Liability Partnership | | 2007 |
| Stockeld Farms Limited | Agriculture & fishing | 1973 |
| Stockwise Yorkshire Limited | Administrative & support | 2007 |
| Stone Vale (Masonry) Limited | Wholesale & retail | 2003 |
| Stonemill Management Limited | Households | 2001 |
| Storage Innovation Limited | Manufacturing | 2020 |
| Streamside Cottage Limited | Households | 2001 |
| Strength in Fragments CIC | Health & social care | 2026 |
| Striano Investments Limited | Financial services | 2024 |
| Stripes Holdings Limited | Financial services | 2026 |
| Stross Holdings Limited | Hospitality | 1987 |
| STS Freight Services Ltd | Transport & logistics | 2013 |
| Stuart Hirst (Holdings) Limited | Professional & scientific | 2005 |