- Sigma Pharmaceuticals PLC (Special Concept Development / RxFarma)
- Sintetica Limited
- Sovereign Medical
- SSL International plc
- Stanningley Pharma Limited
- STD Pharmaceutical Products Ltd
- Steba Biotech
- Stiefel
- Stirling Anglian Pharmaceuticals Ltd
- Strandhaven Limited t/a Somex Pharma
- Strides Pharma UK Ltd
- Swedish Orphan Biovitrum Ltd
- Synchrony Pharma Ltd
- Syner-Medica Ltd