| Stellar Creates CIC | Arts & recreation | 2023 |
| Stellar Projects & Events LLP | | 2016 |
| Stem NE Ltd | Manufacturing | 2019 |
| Steph COM Pany Ltd | Health & social care | 2023 |
| Stephen Downing Consultancy Ltd | Information & communication | 2025 |
| Stephen Mcguigan Electrical Limited | Construction | 2016 |
| Stephen Rose Residential Limited | Real estate | 2017 |
| Stephen Walker Brickwork Limited | Construction | 2018 |
| Stephensons Consulting Engineers (Forensics) Ltd | Professional & scientific | 2012 |
| Stephensons Export Ltd | Wholesale & retail | 2023 |
| Steptoes Footcare Centre Ltd | Health & social care | 2005 |
| Sterling Accountancy & Bookeeping Ltd | Professional & scientific | 2015 |
| Sterling Filtration Ltd | Professional & scientific | 2022 |
| Sterling Heat Solutions Ltd | Construction | 2026 |
| Sterling Mixers Ltd | Manufacturing | 2019 |
| Sterling Recruitment Group Limited | Administrative & support | 2022 |
| Sterling Recruitment Services Limited | Administrative & support | 2018 |
| Sterling Stone Ltd | Wholesale & retail | 2025 |
| Steve Brettle Fabrications Ltd. | Manufacturing | 1999 |
| Steve Brettle Properties Limited | Real estate | 2013 |
| Steve P Ltd | Construction | 2025 |
| Steve Padgett Plumbing & Heating Ltd | Construction | 2026 |
| Steven Toman Consultants Ltd | Real estate | 2022 |
| Stevesfurnishings Ltd | Wholesale & retail | 2020 |
| Sticki Group Ltd | Wholesale & retail | 2026 |
| Sticks and Stones Studios CIC | Information & communication | 2022 |
| Stitch Express Middlesbrough Ltd | Manufacturing | 2017 |
| STO Barbers Ltd | Other services | 2022 |
| Stocc Limited | Wholesale & retail | 2020 |
| Stockdrop Ltd | Wholesale & retail | 2026 |
| Stockton Electrical Services Limited | Manufacturing | 2008 |
| Stockton Leisure Limited | Hospitality | 2013 |
| Stockton Models Limited | Wholesale & retail | 2006 |
| Stockton Social Ltd | Hospitality | 2018 |
| Stoica Plumbing Services Ltd | Construction | 2023 |
| Stokeld Contracts and Commercial Services Limited | Professional & scientific | 2023 |
| Stokesby Chessingston Ltd | Construction | 2025 |
| Stokesley Agricultural Society | Other services | 2024 |
| Stokesley Chippy Ltd | Hospitality | 2024 |
| Stokesley Commercial Services Limited | Professional & scientific | 2016 |
| Stokesley Engineering Ltd | Professional & scientific | 2022 |
| Stokesley Financial Services Limited | Financial services | 2023 |
| Stokesley Golf Range Limited | Arts & recreation | 2011 |
| Stokesley Kitchens Limited | Construction | 2013 |
| Stokesley Property Management Ltd | Households | 2023 |
| Stokesley Property Services Ltd | Real estate | 2025 |
| Stokesley Service Centre Limited | Wholesale & retail | 2021 |
| Stokesley Show Limited | Other services | 2012 |
| Stone Glow Ltd | Construction | 2026 |
| Stonebeck Lettings Ltd | Real estate | 2025 |
| Stonebridge Electrical Ltd | Construction | 2021 |
| Stonehouse Home Improvements Ltd | Construction | 2022 |
| Stoneworks Northeast Limited | Wholesale & retail | 2016 |
| Stoney Bridge Holdings Limited | Financial services | 2023 |
| Stoney Bridge Properties Ltd | Real estate | 2021 |
| Stop & Stay Ltd | Real estate | 2025 |
| Storage 247 Ltd | Administrative & support | 2021 |
| Store Ease Ltd | Transport & logistics | 2024 |
| Storemae Limited | Manufacturing | 2025 |
| Storeyoffshore Ltd | Professional & scientific | 2025 |
| Story & Studio CIC | Arts & recreation | 2024 |
| Storylens Media CIC | Information & communication | 2025 |
| Stovell & Millwater Limited | Professional & scientific | 2015 |
| Straight Pace Limited | Wholesale & retail | 2024 |
| Strategic Appsolutions Limited | Administrative & support | 2014 |
| Strategic Project Consulting Ltd | Professional & scientific | 2020 |
| Strategics Security Ltd | Administrative & support | 2026 |
| Strawberry Fields Accommodation Ltd | Extraterritorial | 1999 |
| Stray Cafe Redcar Limited | Hospitality | 2017 |
| Strictly Average Limited | Hospitality | 2022 |
| Stride North East Limited | Wholesale & retail | 2025 |
| Strive Housing Teesside CIC | Hospitality | 2026 |
| Struqtive NE Limited | Construction | 2020 |
| STS Resources & Technology Limited | Construction | 2007 |
| Stuart Hall & Co (Teesside) Limited | Professional & scientific | 2016 |
| Stucco Masters Limited | Construction | 2025 |
| Studio 1 NE Ltd | Administrative & support | 2025 |
| Studio JB Limited | Professional & scientific | 2025 |
| Studyden Ltd | Information & communication | 2026 |
| Stunt Drive North East Ltd | Arts & recreation | 2012 |
| Styles Precision Prospecting Limited | Professional & scientific | 2024 |
| Stylish Home Solutions Ltd | Administrative & support | 2024 |
| Stylo Sphere Limited | Wholesale & retail | 2025 |
| SU Investments Ltd | Real estate | 2020 |
| Subsea ARC Limited | Professional & scientific | 2019 |
| Sugar Free Solutions Limited | Manufacturing | 2015 |
| Sulemania Ltd | Wholesale & retail | 2018 |
| Sullivan Property Group Ltd | Real estate | 2026 |
| Sultan Store Ltd | Wholesale & retail | 2025 |
| Sumaira Ilyas Limited | Health & social care | 2017 |
| Summerhouse Management Limited | Administrative & support | 2005 |
| Summerhouse Music Limited | Information & communication | 1993 |
| Summerhouse Records Limited | Arts & recreation | 1986 |
| Summit Clothing UK Limited | Wholesale & retail | 2020 |
| Sunderland Hand Car Wash Ltd | Other services | 2021 |
| Sunflower NE Limited | Hospitality | 2025 |
| Sunlight Renewables, Electrical, Design and Facilities Ltd | Construction | 2009 |
| Sunningdale Takeaway Ltd | Hospitality | 2017 |
| Sunray Media Ltd | Information & communication | 2019 |
| Sunsational Ltd | Other services | 2025 |