| Zamzar | Hampshire |
| ZanaNET Ltd | |
| Zanet Design Ltd | Dorset |
| Zanran Ltd | |
| Zanzi Digital | Oxfordshire |
| Zap Creative Ltd | Hampshire |
| Zap-Map | |
| Zapnito Ltd | |
| Zapp Innovation Ltd | |
| Zappar | Greater London |
| Zappar Ltd | |
| Zappr.AI | |
| ZappyAI | Greater London |
| Zarax | |
| Zarr | Warwickshire |
| Zash | |
| Zash Technologies Ltd | |
| Zattikka plc | |
| Zavial Ltd | Somerset |
| Zavvi | Cheshire |
| Zazzle Media | |
| ZC Social Media | Kent |
| ZDEV | Greater London |
| Zealous Solutions Ltd | |
| Zebedee Creations Web Design London | Greater London |
| zebNet | |
| Zebra Computer Solutions Ltd | Greater Manchester |
| Zebra Software Ltd | |
| Zebsys Ltd | Lancashire |
| Zecure | |
| Zed One Internet Services | Cambridgeshire |
| Zed1 Technology Services Ltd | Surrey |
| Zed1.com Ltd | Greater Manchester |
| Zedify | |
| Zeed | |
| Zeelo Ltd | |
| Zeetta Networks Ltd | Bristol |
| Zeevou Ltd | |
| ZEG | |
| Zelst Ltd | North Yorkshire |
| Zelt | |
| Zen Educate Ltd | |
| Zen Internet Ltd | Greater Manchester |
| Zen Systems Ltd | Suffolk |
| ZenBit | Northamptonshire |
| Zencargo | |
| Zenex 5ive Ltd | Berkshire |
| Zengenti | Shropshire |
| Zenith | |
| Zenith Bank (UK) Ltd | |