| The Cube | |
| The Digital Beam | |
| The Smilling Hippo | |
| TheGodFather | Central Macedonia |
| ThessWebsite | |
| TheWebPower | Attica |
| Think Plus | |
| ThinkBag Ltd | Attica |
| Thinkbiz | |
| TicTac Laboratories | Attica |
| TiSoft | Attica |
| TLSoftware.gr | Attica |
| Tool Digital Agency | Attica |
| Top Computer Systems Ltd | Attica |
| Top Electronics Components S.A. | |
| Top.Host | Attica |
| Total Eclipse Games | Central Macedonia |
| TotalWeb | Attica |
| Traptics | |
| TreeD Network | |
| Trust-IT | Attica |
| TrustServers | Attica |
| TTT Global Group | Attica |
| Twinnet | |
| Tzanidakis Service Group | Crete |
| UBITECH | Attica |
| Ubuntu-GR | Attica |
| Umbrella Branding | |
| Uni Systems S.A. | Attica |
| Unibrain.com | Attica |
| Unibyte | |
| Unicorn domain | |
| Union Programming Group | |
| United Fiber | |
| United Online S.A. | Attica |
| University of Crete | |
| University of Crete - Department of Mathematics | Crete |
| University of Ioannina - Department of Computer Science and Engineering | Epirus |
| University of Macedonia | Central Macedonia |
| University of Patras | West Greece |
| University of Patras - Department of Electrical and Computer Engineering | West Greece |
| University of Piraeus | |
| University of the Aegan - Department of Information and Communication Systems Engineering | North Aegean |
| University of the Aegean | |
| University of the Peloponnese | |
| University of Thessaly | |
| University of Western Macedonia | |
| up2metric | |
| UpCommerce | |
| Updated | |