| Irssi | Flemish Brabant |
| Isabel Group | |
| ISIS | Liège |
| ISO-Computer | Namur |
| ISPA Belgium | Brussels-Capital |
| iSTAR Medical | |
| IT Consult Services | |
| IT Partner B.V.B.A. | |
| IT Pro N.V. | Antwerp |
| IT-Nerd Computer Solutions | Antwerp |
| IT1 | East Flanders |
| ITAF IT | East Flanders |
| iText Group N.V. | East Flanders |
| ITLEY Conseils & Services | Brussels-Capital |
| IVA Machine Vision Systems | Flemish Brabant |
| Ivex | |
| Ixor | Antwerp |
| JAAN B.V. | Namur |
| Jalons | Walloon Brabant |
| Jamo Solutions | Flemish Brabant |
| Jaywalk S.P.R.L. | |
| JD Systems B.V.B.A. | West Flanders |
| Jef Vingerhoets Design | Antwerp |
| Job Partner | Brussels-Capital |
| Jobgether | |
| John's Computers | Liège |
| Joliet Service | Liège |
| Joomlatools | Brussels-Capital |
| JTC Micro Electronics N.V. | Limburg |
| June | |
| JvSoft | |
| Kabelwerk Eupen AG | Liège |
| Kangaroot | Antwerp |
| Kantify | |
| Kappa Data Group | |
| Kaspard | |
| Keep IT Running | Limburg |
| Kenetix B.V.B.A. | |
| Keyrock | |
| KeyTech | |
| Keytrade Bank | Brussels-Capital |
| Keyware | Flemish Brabant |
| Keyware Technologies N.V. | |
| Kharis Capital | |
| Kim Communication | Walloon Brabant |
| Kinamo S.A. | Antwerp |
| KiOmed Pharma | |
| Kitencre | Brussels-Capital |
| Kitry | Walloon Brabant |
| KMOSites B.V. | East Flanders |