| L Marks Ltd | |
| L&P Systems Ltd | Merseyside |
| L2P Enterprise Ltd | |
| L3C Ltd | Greater London |
| LAB | |
| Lab 1 | |
| Labcenter Electronics | North Yorkshire |
| Labelneeds Ltd | Cardiff |
| Labelview | |
| LabGenius Ltd | |
| LabGenius Therapeutics | |
| Labman Automation Ltd | North Yorkshire |
| Labman Automation Ltd | |
| Labocon Scientific Ltd | |
| Labrador Computers | |
| Labrys | |
| Labyrinth Computers Ltd | Somerset |
| Labyrinth IT Services Ltd | |
| Lacode.com | |
| Lacoudhir Design Ltd | |
| Lacuna Space Ltd | |
| LadyBird Computing | |
| Lake Chemicals and Minerals Ltd | |
| Lake Financial Systems | West Yorkshire |
| Lakes Computer Consultants Ltd | Lancashire |
| Lakewood Media Ltd | Greater London |
| LaMetric | |
| Laminar Global | |
| Lamp Design Ltd | Swansea |
| LAN Controls | |
| LAN Support Systems Ltd | |
| Lancashire Data Solutions Ltd | |
| Lancaster Hunt Systems | Surrey |
| Lancaster University | Lancashire |
| Lancaster University - Mathematics and Statistics | Lancashire |
| Lancaster University - Quantum Technology Centre | Lancashire |
| Lancaster University - School of Computing and Communications | Lancashire |
| Lancaster University Network Services Ltd | |
| LanceForce Ltd | |
| Land Digital | |
| Land Technologies Ltd | Greater London |
| Landbay Partners Ltd | |
| Lander Tubular Products | |
| LandingNet Ltd | Nottinghamshire |
| Landmark Games | |
| Landmark Systems | West Sussex |
| Landscape Group | Hampshire |
| Landscape Printing Systems Ltd | Hampshire |
| Landscape Software Ltd | Oxfordshire |
| Landscape Ventures | |