| Bigtower | Liège |
| BIO invests | |
| Bio-Incubator Leuven | Flemish Brabant |
| Bio-Sourcing | |
| Biocartis N.V. | |
| BioSenic S.A. | |
| BioStrand | |
| BioVille | |
| Bioxodes | |
| BIPT - IBPT | Brussels-Capital |
| Birdhouse | |
| BISC Global | |
| Bisoft | |
| BIT Computers | East Flanders |
| Bit IT Consultancy | |
| BIT Services | |
| BitLess B.V.B.A. | |
| Bits & Bytes N.V. | Limburg |
| Bits of Love | |
| BizzDev S.A. | |
| BKM | Limburg |
| bkweb | Liège |
| Blindspot | |
| BLISS | |
| Blue Minds | |
| Blue One Management S.A./N.V. | |
| blue2purple | Brussels-Capital |
| Bluecorp S.R.L. | |
| Bluefive software | Antwerp |
| Bmgroup | Antwerp |
| bNamed.net | Antwerp |
| BNP Paribas Fortis | |
| Board of Innovation | Antwerp |
| Boobook | |
| Boondoggle | Flemish Brabant |
| Boot Ventures | |
| BoulevArt N.V. | Antwerp |
| BRAFT S.R.L. | |
| Brainbridge B.V.B.A. | Antwerp |
| Brainpoint | Flemish Brabant |
| Brainstorming | Liège |
| BrainWin | Flemish Brabant |
| Branspace | |
| Bricsys N.V. | |
| Bright Analytics B.V. | West Flanders |
| BrightSoft | West Flanders |
| Brother International (Belgium) N.V. | Flemish Brabant |
| BruCON | Flemish Brabant |
| Brussels Innova | Brussels-Capital |
| Brussels Life Science Incubator | |