| RazrCorp | Luxembourg |
| RazrCorp | |
| RazrTech | |
| Rcarré S.A. | Capellen |
| RCDevs S.A. | Esch-sur-Alzette |
| RealCorp | |
| Reborn | |
| Red Dog Communications | Luxembourg |
| Référenceur | |
| Regus | |
| Research Industry Collaboration | |
| Research Luxembourg | |
| RespectUs | |
| Ricoh Luxembourg PSF S.à.r.l. | Luxembourg |
| RISE | |
| RiverBank S.A. | |
| RoomMate S.A. | |
| Root S.A. | Mersch |
| Rotarex | |
| RSS-Hydro | |
| RTC4Water | |
| Runa Capital | |
| Sacred Heart University Luxembourg | |
| Santé Services | |
| Satgana | |
| Satispay Europe S.A. | Luxembourg |
| Savvy Mobility | |
| SBM Luxembourg | Capellen |
| Schaller Electronic S.à.r.l. | Luxembourg |
| SEA-Invest | |
| SeeReal Technologies S.A. | |
| SES S.A. | Grevenmacher |
| SFR Luxembourg | Luxembourg |
| Shipsta S.à r.l. | |
| ShortDot | |
| Signalhorn AG | Luxembourg |
| Silicon DNA | Luxembourg |
| Silicon Luxembourg | Luxembourg |
| Simile Venture Partners | Luxembourg |
| simpleshow | |
| SIMS Solutions S.à.r.l. | Luxembourg |
| SIP Discount | Luxembourg |
| SIPTraffic | Luxembourg |
| Sisvel International S.A. | Luxembourg |
| Sit-Net S.A. | Esch-sur-Alzette |
| Sita Software S.A. | Esch-sur-Alzette |
| Skeeled HR S.à r.l. | |
| Skelia S.à.r.l. | |
| SkyCom S.à r.l. | Grevenmacher |
| Skyline Network Services AG | Clervaux |