| Image Coa: | DEU Oststeinbek COA.svg |
| Coordinates: | 53.5442°N 10.1664°W |
| Image Plan: | Oststeinbek in OD.svg |
| State: | Schleswig-Holstein |
| District: | Stormarn |
| Elevation: | 25 |
| Area: | 11.37 |
| Postal Code: | 22113 |
| Area Code: | 040 |
| Licence: | OD |
| Gemeindeschlüssel: | 01 0 62 053 |
| Divisions: | 2 |
| Website: | www.oststeinbek.de |
| Mayor: | Jürgen Hettwer[1] |
Oststeinbek is a municipality in the district of Stormarn, in Schleswig-Holstein, Germany. It is situated approximately 13 kilometres east of the center of Hamburg, directly on the border between Hamburg and Schleswig-Holstein.
First mentioned in 1254 it celebrated its 750th anniversary in 2004.
As of 2011, Oststeinbek had about 8600 inhabitants.