| Osterby Østerby | |
| Image Coa: | DEU Osterby (Kreis Schleswig-Flensburg) COA.svg |
| Coordinates: | 54.7833°N 22°W |
| Image Plan: | Osterby in SL.PNG |
| State: | Schleswig-Holstein |
| District: | Schleswig-Flensburg |
| Amt: | Schafflund |
| Elevation: | 26 |
| Area: | 12.35 |
| Postal Code: | 24994 |
| Area Code: | 04605 |
| Licence: | SL |
| Gemeindeschlüssel: | 01 0 59 151 |
| Website: | www.amt- schafflund.de |
| Mayor: | Arnold Nommensen |
Osterby (Danish: Østerby) is a municipality in the district of Schleswig-Flensburg, in Schleswig-Holstein, Germany.