OY
| Acronym | Definition |
|---|---|
| OY | Osakeyhtiö (Finnish: limited company) |
| OY | Optimum Yield |
| OY | Osakeyhtio (Finnish: Limited/Incorporated) |
| OY | Option Year |
| OY | Operating Year |
| OY | Organizing Youth |
| OY | Outyear |
| OY | Oxana Yablonskaya (classical pianist) |
| OY | New Zealand Life Insurance Stamp (Scott Catalogue prefix; philately) |
| OY | Code for Danish Aero Plane |