| Quinteq Consulting Limited | Information & communication | 2018 |
| R & B Andreas Ltd | Health & social care | 2010 |
| R & L Bugden Ltd | Real estate | 2014 |
| R&A Productions Ltd | Information & communication | 2015 |
| R. Rademaker Trading Limited | Wholesale & retail | 2001 |
| R.Kirk Limited | Wholesale & retail | 2008 |
| R.Z.G Mechanical Limited | Wholesale & retail | 2021 |
| Radclyffe Furniture Limited | Professional & scientific | 2010 |
| Radical Shock Limited | Manufacturing | 1999 |
| Radley & SON Building Services Limited | Construction | 2008 |
| Rail Engineering Group Limited | Professional & scientific | 2017 |
| Railspec Consulting Ltd | Professional & scientific | 2018 |
| Rainbow Roast Cafe Ltd | Hospitality | 2023 |
| Rallynuts Limited | Manufacturing | 2017 |
| Rambunctious Solutions Limited | Information & communication | 2021 |
| Ranson Consultancy Limited | Information & communication | 2018 |
| Rare Breed Writing Ltd | Professional & scientific | 2020 |
| Rather Good Consultancy Ltd | Information & communication | 2018 |
| Ravens Court (Long Marston) Residents Company Limited | Administrative & support | 2003 |
| RCC Limited | Professional & scientific | 2016 |
| Rdm&S Consultants Limited | Professional & scientific | 2012 |
| RDR Property Services Limited | Real estate | 2016 |
| Rebecca Hale Limited | Information & communication | 2025 |
| Recce and Hollie Limited | Real estate | 2017 |
| Recmotion Ltd | Information & communication | 2022 |
| Red Deer Mortgages and Protection Limited | Financial services | 2026 |
| Red Hot Live Limited | Arts & recreation | 2017 |
| Red Kite Creative Limited | Arts & recreation | 2016 |
| Red Viking Consultancy Ltd | Information & communication | 2018 |
| Redsen Limited | Information & communication | 2013 |
| Redwing Farm Management Company Limited | Households | 2011 |
| Reece and Hollie Ltd | Real estate | 2021 |
| Regal Court Residents Association (Tring) Limited | Professional & scientific | 1987 |
| Remusable Limited | Manufacturing | 2022 |
| Rencore Energy Ltd | Professional & scientific | 2016 |
| Renewon Limited | Energy | 2020 |
| REP Arena Limited | Information & communication | 2025 |
| Requiem Cards Limited | Wholesale & retail | 2026 |
| Resonance (UK) Limited | Information & communication | 2002 |
| Responsible Feedstuff Sourcing (UK) Ltd | Professional & scientific | 2025 |
| REX Propsol Ltd | Real estate | 2025 |
| RFJ Consulting Services Limited | Professional & scientific | 2020 |
| RGC Roofing and Guttering Ltd | Construction | 2021 |
| RGS Global Ltd | Information & communication | 2025 |
| RH Solutions Limited | Information & communication | 2019 |
| RHL Consultants Ltd | Construction | 2014 |
| Rick Coleman Ltd | Arts & recreation | 2018 |
| Rickyard Ltd. | Agriculture & fishing | 1983 |
| Ridgestone Solutions Ltd | Construction | 2023 |
| Ridgeway Learning Partnership | Education | 2012 |
| Riggledy Piggledy Solutions Ltd | Construction | 2023 |
| Riley Accountants Limited | Professional & scientific | 2013 |
| Riley Financial Limited | Financial services | 2017 |
| Riverdale Build & Construct Limited | Construction | 2020 |
| Riverdale Stone Limited | Construction | 2006 |
| Riverline Consulting Ltd | Professional & scientific | 2021 |
| RJ Wigginton Ltd | Information & communication | 2019 |
| RM Forster Consulting Limited | Information & communication | 2017 |
| RM Group of Companies Ltd | Financial services | 2025 |
| Rmdolling Ltd | Health & social care | 2023 |
| Rmheritage Ltd | Professional & scientific | 2025 |
| Roadrunner Productions Ltd | Information & communication | 2015 |
| Robertson Associates (Surveyors) Limited | Construction | 2003 |
| Rock Masters Global Ltd | Health & social care | 2025 |
| Rock Physics Associates Limited | Professional & scientific | 1999 |
| Rockcorry Ltd | Real estate | 2015 |
| Rocket Badger Technology Limited | Information & communication | 2022 |
| Rockshine Ltd. | Real estate | 2016 |
| Rocky-Messissi Limited | Information & communication | 2025 |
| Roma Electrical Contracting Services Limited | Construction | 2016 |
| Rory Snowball TV Ltd | Information & communication | 2023 |
| Rose Services Limited | Information & communication | 2015 |
| Ross Spindle Video Playback Ltd | Information & communication | 2003 |
| Ross Williams Limited | Information & communication | 2001 |
| Rossi Networks Limited | Information & communication | 2018 |
| Roundproud Limited | Other services | 1991 |
| Rowans Consulting Services Limited | Professional & scientific | 2019 |
| ROY Chapman Limited | Wholesale & retail | 1988 |
| RRH Advisory Limited | Professional & scientific | 2026 |
| RRN Solutions Ltd | Information & communication | 2023 |
| Rszac Consultancy Limited | Financial services | 2013 |
| RT Platform Ltd | Information & communication | 2026 |
| Rubus Ilex Ltd | Professional & scientific | 2019 |
| Ruby Blue Ltd | Information & communication | 2019 |
| Run the Wild Limited | Administrative & support | 2013 |
| Runway 27 Limited | Wholesale & retail | 2013 |
| RX Performance Ltd | Wholesale & retail | 2024 |
| Ryan Carter Consultants Ltd | Professional & scientific | 2020 |
| Ryan Coughlan Ltd | Professional & scientific | 2019 |
| Ryan Handy Studio Ltd | Professional & scientific | 2025 |
| S Arnold Developments Limited | Construction | 2021 |
| S Blaxley Construction Ltd | Construction | 2023 |
| S J Moxom Limited | Construction | 2002 |
| S J Ring Electrical Limited | Construction | 2011 |
| S. Wigglesworth HR Consulting Ltd | Professional & scientific | 2022 |
| S.M.T Automotive Ltd | Wholesale & retail | 2019 |
| S77FAL Ltd | Professional & scientific | 2009 |
| Sacred YEW Estates Limited | Real estate | 2023 |
| SAI GMT Solutions Limited | Information & communication | 2017 |
| SAI Technology Solutions Ltd | Information & communication | 2021 |