| Angels Den | |
| Angels in MedCity | |
| Angels Media Ltd | |
| Angels Partners | |
| Angiodesign (UK) Ltd | Wiltshire |
| Angle plc | |
| Angle Studios | |
| Anglia Research Services | |
| Anglia Ruskin University | Cambridgeshire |
| Anglia Ruskin University - Computing and Information Science | Cambridgeshire |
| Anglia Telephones | Norfolk |
| Anglian Internet | |
| Anglian Internet Ltd | Norfolk |
| Anglian Linux User Group | Norfolk |
| ANGOKA Ltd | |
| Angry Creative UK Ltd | |
| Angular Ventures | Greater London |
| Anicca Digital | |
| Anika Digital | |
| Animacs | Cambridgeshire |
| Animal Systems Ltd | Wiltshire |
| Animated Technologies Ltd | |
| Animo Consultancy | |
| Animorph Ltd | |
| Animus Technology | |
| ANNA | |
| Annexio Ltd | Isle of Man |
| Annodata Ltd | Hertfordshire |
| Anopia Digital | |
| Anorak | Greater London |
| Anorak Technologies Ltd | Greater London |
| Anota Ltd | |
| Another Round | |
| ANS Group | Greater Manchester |
| Answer Digital Ltd | West Yorkshire |
| Answers 2000 Ltd | Buckinghamshire |
| ANT Telecom | Buckinghamshire |
| Antal International | |
| Antavo | |
| AntennaWare Ltd | |
| Antenova Ltd | Hertfordshire |
| Antev Ltd | |
| Antex (Electronics) Ltd | Devon |
| Anthemion Software Ltd | Edinburgh |
| Antibodies.com | |
| Antibody Analytics Ltd | |
| Antibody Production Services | |
| Antikor | |
| Antiquity Software | Hertfordshire |
| Antiverse | |