| XAnge | Paris |
| Xankom | Finistère |
| Xavier Robion Conseil | Yvelines |
| Xdebug | Paris |
| XDi | |
| XEFI | Métropole de Lyon |
| Xegen | |
| Xeilom | Aisne |
| Xelya | Hauts-de-Seine |
| Xenocs S.A.S. | Isère |
| Xenothera | |
| XenTech | |
| Xerox France | |
| Xerus S.A.S. | Métropole de Lyon |
| Xfly | Métropole de Lyon |
| XGI | Lozère |
| Xilabs | Paris |
| Xilan | Nord |
| Xilinus | |
| XiVO Solutions | Métropole de Lyon |
| XL Soft | Loire-Atlantique |
| XLEARN | |
| XLIM | Haute-Vienne |
| XLSTAT | Paris |
| XMCO | |
| XML C parser and toolkit of Gnome | Isère |
| XMLmind | Yvelines |
| Xmloperator | Hauts-de-Seine |
| Xname | Hauts-de-Seine |
| XnView | Marne |
| xo7 | |
| Xooit S.A.R.L. | Paris |
| XOOPS France | Loir-et-Cher |
| XPERTEAM | Hauts-de-Seine |
| XQual | Alpes-Maritimes |
| XR+ | |
| Xsalto | Isère |
| XSun | |
| XtendPlex | |
| XTR4L1F3 | |
| XtreemOS | Ille-et-Vilaine |
| XWiki | Paris |
| XXII Group | |
| Y SCHOOLS | |
| Y-Proximité | Paris |
| Yaal Coop | |
| Yacast | Paris |
| Yalty | |
| Yamgaille | Paris |
| Yampa | |