| Social Justice Movement CIC | Arts & recreation | 2022 |
| Socialcave Ltd | Information & communication | 2025 |
| Socialessence Limited | Administrative & support | 2024 |
| Socially Enterprising Services Limited | Information & communication | 2011 |
| Societe Financiere Limited | Professional & scientific | 2008 |
| Society Cafe Limited | Hospitality | 2011 |
| Society of the Salutation of Mary the Virgin Limited(The) | Other services | 1950 |
| Socrates Recruitment Ltd | Administrative & support | 2024 |
| Sofisticato Limited | Real estate | 2017 |
| Soft Stop Ltd | Professional & scientific | 2025 |
| Softech IT Services Ltd | Information & communication | 2010 |
| Software Imaging Limited | Information & communication | 1983 |
| Software Imaging Technology Limited | Information & communication | 2010 |
| Software That Works Limited | Information & communication | 1996 |
| Sohento PT78 Limited | Wholesale & retail | 2025 |
| Soinventive Ltd | Information & communication | 2026 |
| SOK Aesthetics Ltd | Other services | 2025 |
| Sokol Construction Ltd | Construction | 2019 |
| Sola Activewear Ltd | Manufacturing | 2025 |
| Solace in Oxford Ltd | Hospitality | 2024 |
| Solar Panel Ace Ltd | Construction | 2022 |
| Solely Ltd | Hospitality | 2026 |
| Solid Software (Oxford) Limited | Information & communication | 2004 |
| Solid State Logic Holdings Limited | Professional & scientific | 2011 |
| Sollershott Residents Association Limited | Hospitality | 1978 |
| Solme Limited | Administrative & support | 2016 |
| Solo Comb Limited | Wholesale & retail | 1995 |
| Solo Syrian Kitchen Ltd | Hospitality | 2024 |
| Solomon Academic Trust | Education | 2008 |
| Solrah Solutions Limited | Information & communication | 2013 |
| Solution AI X Limited | Information & communication | 2026 |
| Solution EU Holdings Ltd | Financial services | 2015 |
| Solution International Holdings Limited | Financial services | 2022 |
| Solutions Resource Group Limited | Financial services | 2014 |
| Solved Tax Services Limited | Professional & scientific | 2026 |
| Soma CBD Ltd | Wholesale & retail | 2025 |
| Somerton Wharf Limited | Extraterritorial | 2014 |
| Somerville College Developments Limited | Construction | 2016 |
| Somerville College Trading Limited | Hospitality | 2010 |
| Somhi Barca Limited | Wholesale & retail | 2025 |
| Somnix Limited | Health & social care | 2025 |
| Song of the Wild Swan Ltd | Wholesale & retail | 2011 |
| Sonic Events Limited | Administrative & support | 2006 |
| Sonnet-I Ltd | Professional & scientific | 2005 |
| Sonny's Plumbing & Heating Ltd | Construction | 2020 |
| Sonox Initiative Ltd | Public administration | 2025 |
| Sophie Hackford Ltd | Professional & scientific | 2014 |
| Sophie Wade Ltd | Professional & scientific | 2025 |
| SOR Haulage Ltd | Transport & logistics | 2020 |
| Sore Thumb Holdings Ltd | Professional & scientific | 2019 |
| Sormland Ltd | Public administration | 2018 |
| Sortax Accountants Ltd | Professional & scientific | 2024 |
| Sortlist Ltd | Administrative & support | 2014 |
| Sortlist Wholesale Ltd | Wholesale & retail | 2025 |
| Soth Founder Company Limited | Financial services | 2022 |
| Soul Event Ltd | Arts & recreation | 2018 |
| Soul Movement C.I.C. | Arts & recreation | 2015 |
| Soul Restore CIC | Other services | 2022 |
| Soulworm Limited | Wholesale & retail | 2008 |
| Soundabout | Education | 2004 |
| Soundtheory Limited | Information & communication | 2015 |
| Source Market Access Ltd | Professional & scientific | 2016 |
| Sourcing Bridge Ltd | Professional & scientific | 2006 |
| South Central Gospel Partnership | Other services | 2012 |
| South London Developments Limited | Real estate | 2005 |
| South Oxford Arts CIC | Arts & recreation | 2025 |
| South Oxford Building Services Ltd. | Construction | 2013 |
| South Oxford Electrical Services Ltd | Construction | 2012 |
| South Oxford Family Room CIC | Health & social care | 2025 |
| South Oxfordshire Science Village Developments Limited | Construction | 2024 |
| South Parade Enterprises Limited | Wholesale & retail | 2020 |
| South Rose LLP | | 2017 |
| Southern Cross Space Engineering Limited | Professional & scientific | 2023 |
| Southernmost Limited | Other services | 2017 |
| Southfield Court Residents Association (Oxford) Limited | Households | 1998 |
| Southmoor Studio Limited | Arts & recreation | 2022 |
| Southseas Property Investment Limited | Administrative & support | 2014 |
| Southstar.Io Ltd | Professional & scientific | 2021 |
| SOW Space Ltd | Professional & scientific | 2019 |
| Soyanme Food Ltd | Hospitality | 2018 |
| SP Oxford Ltd | Arts & recreation | 2025 |
| SP1 Solutions Limited | Information & communication | 2015 |
| Space Cileide Cordeiro Ltd | Other services | 2018 |
| Space Program Ltd | Professional & scientific | 2013 |
| Spacics Limited | Wholesale & retail | 2021 |
| Spackman's Sons Limited | Manufacturing | 2024 |
| Spanner Works Oxford Ltd | Wholesale & retail | 2017 |
| Spark Assessment Services Limited | Professional & scientific | 2012 |
| Spark Wise Electrical Ltd | Construction | 2024 |
| Spark Wize Ltd | Construction | 2026 |
| Sparkhouse Productions Limited | Information & communication | 2003 |
| Sparklean.Ox Ltd | Households | 2015 |
| Sparkling Minds Ltd | Education | 2020 |
| Sparkling Minds Pre-School & Day Nursery Ltd | Education | 2009 |
| Sparkora Ltd | Wholesale & retail | 2026 |
| Sparks Publishing Services Limited | Information & communication | 2007 |
| Spartacus Medical Ltd | Health & social care | 2019 |
| Spaul Holdings Limited | Real estate | 2016 |
| Speaken Education Ltd. | Education | 2015 |
| Speaking of Words Ltd | Health & social care | 2021 |