OStR
| Acronym | Definition |
|---|---|
| OStR | Oberstudienrat (Austria, Europe) |
| OStR | Orchestre Symphonique de Trois-Rivières (Canada) |
| OStR | Optimum Speed Tilt Rotor (Karem Aircraft) |
| OStR | Optical Single Transporter Recording |
| OStR | Oblates of St. Therese Reformed (religious order) |
| OStR | On-Site Technical Representative |