| KPMD (IT Solutions) Ltd | South Yorkshire |
| KPR Midlink Ltd | West Midlands |
| Kraken Technologies Ltd | |
| KrakenFlex Ltd | |
| Kratos Analytical Ltd | |
| KRCS Group Ltd | Nottinghamshire |
| Krea8iv Software Solutions | |
| Kreative Dimension Web Design Edinburgh | |
| Kreos Capital | |
| Kriya Finance Ltd | |
| Krotos Ltd | |
| Krucial | |
| Kruve | |
| Kryotech Group Ltd | |
| Krystal Hosting Ltd | Greater London |
| KSL Training | Berkshire |
| Kt.team | |
| KTD | West Yorkshire |
| KualitySoft | |
| Kuano | Greater London |
| KUB Ltd | Greater Manchester |
| Kuberno Ltd | |
| Kubla Ltd | |
| Kubos Semiconductors Ltd | |
| Kubuntu | Isle of Man |
| Kudian Software | Warwickshire |
| Kudos Software Ltd | Devon |
| Kuki Ventures Ltd | Nottinghamshire |
| KulaHub Ltd | North Yorkshire |
| Kulea.ma | |
| Kurtosys Systems | |
| KV Computer Services Ltd | Tyne and Wear |
| KVC (UK) Ltd | West Dunbartonshire |
| KVM Choice Ltd | Surrey |
| KVM Switch Direct | Dorset |
| KW Design Nottingham Ltd | |
| KWA Analytics Ltd | |
| Kwest Research Ltd | |
| Kx Systems | Newry, Mourne and Down |
| Kyan | |
| Kyanite Consulting Ltd | Lincolnshire |
| Kymab Ltd | |
| KYND | |
| Kynet Ltd | Hertfordshire |
| Kynetix | |
| KYOCERA Document Solutions (U.K.) Ltd | Berkshire |
| Kyte Tech, Inc. | |
| Kythera AI | |
| Kyttaro Ltd | |
| L & N Radio Ltd | Kent |