| North Reston Landfill Limited | Water & waste | 2003 |
| NRB Roadphone Group Limited | Information & communication | 2002 |
| NSU Leisure Limited | Hospitality | 2003 |
| Oakdene Sleaford Limited | Health & social care | 1995 |
| Odda Farm Sustainable Ventures Ltd | Other services | 2022 |
| Old Barn Antiques Limited | Wholesale & retail | 2006 |
| Old Leake Grain Storage Limited | Transport & logistics | 1999 |
| Ollytommymax Limited | Professional & scientific | 2004 |
| OLY RAY Limited | Agriculture & fishing | 2023 |
| Opus Software Limited | Information & communication | 1987 |
| Ormeley Road Limited | Real estate | 2021 |
| Overton (UK) Limited | Manufacturing | 1992 |
| P. T. Moore Farms Limited | Agriculture & fishing | 1997 |
| P.C.Coaches of Lincoln Limited | Transport & logistics | 1999 |
| P.T. Potter Electrical Services Limited | Construction | 2000 |
| PA Property Consultants Limited | Professional & scientific | 2002 |
| Pacha Nights Limited | | 1987 |
| Pallinc Holdings Limited | Financial services | 2025 |
| Parker's Funeral Directors of Lincolnshire Limited | Other services | 2003 |
| Parkinsons Fish and Chips Limited | Hospitality | 2003 |
| Paul Chafer Welding Ltd | Construction | 2003 |
| Paul Harland Electrical Limited | Construction | 2006 |
| Paul Kierman Plumbing and Heating Limited | Construction | 2009 |
| PDQ Payments Limited | Wholesale & retail | 2007 |
| Peakhill Associates Ltd | Agriculture & fishing | 2002 |
| Peking Chef LN9 Ltd | Hospitality | 2019 |
| Pell of Belton Limited | Extraterritorial | 1954 |
| Pennell's Holdings Limited | Wholesale & retail | 2006 |
| PEOPLE2KNOW Limited | Professional & scientific | 2000 |
| Periam & Williamson Limited | Construction | 1999 |
| Peter Jackson Cabinet Maker Limited | Construction | 2002 |
| Peter Scott Shoes Limited | Wholesale & retail | 2003 |
| Philip Cowan Interiors Limited | Manufacturing | 1998 |
| Pickering and Purle Construction Limited | Construction | 2003 |
| Pickwell Limited | Transport & logistics | 2002 |
| Pixel Publishing Limited | Information & communication | 2007 |
| Plantrusion International Limited | Manufacturing | 2005 |
| Playtowers Limited | Arts & recreation | 1999 |
| Pledgers Limited | Wholesale & retail | 2007 |
| PMK Recycling Limited | Water & waste | 2005 |
| PNC Shopfitters Limited | Construction | 2005 |
| Poplar Farm (Plungar) Limited | Real estate | 1987 |
| Port of Boston Limited | Transport & logistics | 1987 |
| Porter.Hdd. Limited | Construction | 2025 |
| Portland Kindergarten Ltd | Education | 2002 |
| Positive Health (Lincolnshire) | Health & social care | 2001 |
| Postpack Ltd | Manufacturing | 2002 |
| Powell International Limited | Wholesale & retail | 1955 |
| Prescott & Bellamy Limited | Hospitality | 2007 |
| Primal Victory Limited | Arts & recreation | 2006 |
| Progressive Packaging Systems Limited | | 1980 |
| Pump Sounds Limited | Arts & recreation | 2000 |
| Pygott & Crone Estate Agents Limited | Real estate | 2007 |
| Pygott & Crone Holdings Limited | Professional & scientific | 2007 |
| Pyxis Wholesale Ltd | Wholesale & retail | 2017 |
| R & R Classic Trucks Limited | Wholesale & retail | 2006 |
| R & T (Boston) Limited | Health & social care | 2006 |
| R C L -Rock Constructions Limited | Manufacturing | 2000 |
| R H C Hire Limited | Administrative & support | 2003 |
| R Mason Limited | Other services | 2003 |
| R. & a. Salter Limited | Real estate | 1942 |
| R. Bratley (Quadring) Limited | Agriculture & fishing | 1962 |
| R. Jackson Limited | Real estate | 1992 |
| R. Longstaff & Co LLP | | 2006 |
| R. Toynton Plumbing and Heating Ltd | Construction | 2005 |
| R.H.F - E.T.P Limited | Hospitality | 2004 |
| R.P. Watts (Baston FEN) Limited | Agriculture & fishing | 1992 |
| Racetorations Limited | Manufacturing | 1998 |
| Rampart Investments Limited | Households | 1997 |
| RBS Engineers Ltd | Information & communication | 2014 |
| Red Exchange Limited | Administrative & support | 2007 |
| Red Homes Properties Limited | Real estate | 2017 |
| Redhill Farm (Free Range Pork) Limited | Agriculture & fishing | 2005 |
| Reedman Services Ltd | Professional & scientific | 2005 |
| Reflect Recruitment Group Limited | Administrative & support | 2006 |
| Reflect Recruitment Legal Limited | Administrative & support | 2006 |
| Reflect Recruitment Limited | Administrative & support | 2006 |
| Retford Wallcoverings Limited | Manufacturing | 1999 |
| RHT (Plumbing & Heating Engineers) Limited | Construction | 2003 |
| Richard Brown (Estate Management) Limited | Construction | 2004 |
| Richard Brundell Limited | Construction | 2021 |
| Richard Gadd Interiors Limited | Construction | 2001 |
| Rick Howell Structural Steelwork Limited | Construction | 1986 |
| Riddel Homes Limited | Construction | 2005 |
| RM Crowder Limited | Professional & scientific | 2007 |
| RND Electrical Limited | Wholesale & retail | 2002 |
| Roadphone Limited | Information & communication | 2001 |
| Robert Foster and SON Limited | Wholesale & retail | 1976 |
| Robert Watts Limited | Agriculture & fishing | 1992 |
| Roberts Tyres Limited | Wholesale & retail | 2003 |
| Robinson Refrigeration (Lincs) Limited | Construction | 2001 |
| Rock NET Quarries Ltd | Mining & quarrying | 2007 |
| Rock NET Zero Ltd. | Mining & quarrying | 2007 |
| Rockforce Holdings Limited | Financial services | 2025 |
| Roines Limited | Professional & scientific | 1988 |
| Roman Bank Bakery Limited | Manufacturing | 2000 |
| Roror Limited | Real estate | 2001 |
| Rothwell House Investments Limited | Construction | 1972 |
| Rowhire Limited | Administrative & support | 2006 |
| RTK Stamford Ltd | Professional & scientific | 2005 |